WO2018120514A1

WO2018120514A1 - Qled device and preparation method therefor

Info

Publication number: WO2018120514A1
Application number: PCT/CN2017/080618
Authority: WO
Inventors: 曹蔚然; 杨一行; 刘政; 钱磊
Original assignee: Tcl集团股份有限公司
Priority date: 2016-12-30
Filing date: 2017-04-14
Publication date: 2018-07-05

Abstract

A quantum dot light-emitting diode (QLED) device and a preparation method therefor, comprising a substrate (11), a reflective anode (12), a hole transport layer (14), a quantum dot light-emitting layer (15), an electronic transport layer (16) and a transparent cathode (17) that are sequentially laminated. The quantum dot light-emitting layer is prepared using a quantum dot material having a quantum well energy level structure, and the quantum dot material comprises at least one quantum dot structural unit which is arranged in sequence in a radial direction; the quantum dot structural unit is a graded alloy component structure whose energy level width changes in the radial direction or is a uniform component structure whose energy level width is consistent in the radial direction. The present invention may achieve a high-efficiency QLED device having excellent capabilities such as high-efficiency charge injection, high light-emitting brightness, low driving power supply and high device efficiency.

Description

QLED device and preparation method thereof

Technical field

The invention relates to the field of quantum dots technology, in particular to a QLED device and a preparation method thereof.

Background technique

Quantum dots are special materials that are limited to the order of nanometers in three dimensions. This remarkable quantum confinement effect makes quantum dots have many unique nano properties: the emission wavelength is continuously adjustable, and the emission wavelength is narrow. Wide absorption spectrum, high luminous intensity, long fluorescence lifetime and good biocompatibility. These characteristics make quantum dots have broad application prospects in the fields of flat panel display, solid state lighting, photovoltaic solar energy, and biomarkers. Especially in flat panel display applications, Quantum dot light-emitting diodes (QLEDs) based on quantum dot materials have been displaying image quality, device performance, and performance by virtue of the characteristics and optimization of quantum dot nanomaterials. Manufacturing costs and other aspects have shown great potential. Although the performance of QLED devices has been continuously improved in recent years, there are considerable gaps between the performance requirements of industrial devices and the basic device performance parameters such as device efficiency and device operation stability, which also greatly hinders quantum. Development and application of point electroluminescent display technology. In addition, not only QLED devices, but also in other fields, quantum dot materials have been paid more and more attention to the characteristics of traditional materials, such as photoluminescent devices, solar cells, display devices, photodetectors, bioprobes, and nonlinear optics. Etc., the following only describes the QLED device as an example.

Although quantum dots have been researched and developed as a classic nanomaterial for more than 30 years, the research time of using the excellent luminescent properties of quantum dots and applying them as luminescent materials in QLED devices and corresponding display technologies is still short; Therefore, the development and research of most of the current QLED devices are based on the quantum dot materials of the existing classical structural systems. The corresponding standards for the screening and optimization of quantum dot materials are basically based on the luminescent properties of quantum dots themselves such as quantum dots. Starting from the luminescence peak width, solution quantum yield, and the like. Applying the above quantum dots directly to the QLED device structure to obtain Corresponding device performance results.

However, QLED devices and corresponding display technologies are a complex optoelectronic device system, and there are many factors that affect the performance of the device. Starting from the quantum dot material that is the core luminescent layer material, the quantum dot performance metrics that need to be weighed are much more complicated.

First, quantum dots exist in the form of solid-state films of quantum dot luminescent layers in QLED devices. Therefore, the luminescent properties of quantum dot materials originally obtained in solution may show significant differences after forming solid films: for example In the solid film, the luminescence peak wavelength will have different degrees of red shift (moving to long wavelength), the luminescence peak width will become larger, and the quantum yield will be reduced to different extents, that is, the quantum luminescent material has excellent luminescence in solution. Performance is not fully inherited into the quantum dot solid state film of QLED devices. Therefore, in designing and optimizing the structure and synthetic formulation of quantum dot materials, it is necessary to simultaneously consider the optimization of the luminescent properties of the quantum dot material itself and the luminescence inheritance of the quantum dot material in the state of the solid film.

Secondly, the luminescence of quantum dot materials in QLED devices is achieved by electro-excitation, that is, energization of holes and electrons from the anode and cathode of the QLED device, respectively, and the transport of holes and electrons through the corresponding functional layers in the QLED device. After the quantum dot luminescent layer is combined, photons are emitted by means of radiation transitions to achieve luminescence. It can be seen from the above process that the luminescent properties of the quantum dots themselves, such as luminescence efficiency, only affect the efficiency of the radiation transition in the above process, and the overall luminescence efficiency of the QLED device is also affected by the charge of holes and electrons in the quantum dot material in the above process. Injection and transport efficiency, relative charge balance of holes and electrons in quantum dot materials, recombination of holes and electrons in quantum dot materials, and the like. Therefore, in designing and optimizing the structure of quantum dot materials, especially the fine core-shell nanostructures of quantum dots, it is also necessary to consider the electrical properties of quantum dots after forming solid films: for example, charge injection and conduction properties of quantum dots, fineness of quantum dots. Energy band structure, exciton lifetime of quantum dots, etc.

Finally, considering that QLED devices and corresponding display technologies will be prepared in the future by solution methods such as inkjet printing, which are advantageous in production cost, the material design and development of quantum dots need to consider the processing properties of quantum dot solutions, such as quantum dot solutions. Or the dispersible solubility of the printed ink, Colloidal stability, print film formation, and the like. At the same time, the development of quantum dot materials is also coordinated with the other functional layer materials of QLED devices and the overall fabrication process and requirements of the devices.

In short, the traditional quantum dot structure design, which only considers the improvement of the quantum dot self-luminescence performance, can not meet the comprehensive requirements of QLED devices and corresponding display technologies for the optical properties, electrical properties and processing properties of quantum dot materials. The fine core-shell structure, composition, energy level, etc. of the quantum dot luminescent material need to be tailored to the requirements of the QLED device and the corresponding display technology.

Due to the high surface atomic ratio of quantum dots, atoms that do not form a non-covalent bond with the surface ligand (Ligand) will exist in a surface defect state, which will cause a transition of the non-radiative pathway, thereby The quantum yield of luminescence of quantum dots is greatly reduced. In order to solve this problem, a semiconductor shell layer containing another semiconductor material can be grown on the outer surface of the original quantum dot to form a core-shell structure of the quantum dot, which can significantly improve the luminescent properties of the quantum dot and increase the quantum. Point stability.

The quantum dot materials that can be applied to the development of high-performance QLED devices are mainly quantum dots with a core-shell structure, the core and shell components are respectively fixed and the core shell has a clear boundary, such as a quantum dot having a CdSe/ZnS core-shell structure (J. Phys. Chem., 1996, 100(2), 468–471), quantum dots having a CdSe/CdS core-shell structure (J. Am. Chem. Soc. 1997, 119, (30), 7019‐7029), with Quantum dots of CdS/ZnS core-shell structure, quantum dots with CdS/CdSe/CdS core+multilayer shell structure (Patent US 7,919,012 B2), quantum dots with CdSe/CdS/ZnS core+multilayer shell structure J. Phys. Chem. B, 2004, 108 (49), 18826 - 18831) and the like. In the quantum dots of these core-shell structures, the composition of the core and the shell is generally fixed and different, and is generally a binary compound system composed of a cation and an anion. In this structure, since the growth of the core and the shell are independently performed, the boundary between the core and the shell is clear, that is, the core and the shell can be distinguished. The development of such core-shell quantum dots has improved the quantum efficiency, monodispersity, and quantum dot stability of the original single-component quantum dots.

The quantum dots of the core-shell structure described above partially improve the performance of the quantum dots, but The idea is still based on the improvement of the luminous efficiency of the quantum dot itself, and its luminescence performance needs to be improved. In addition, the special requirements of QLED devices for other aspects of quantum dot materials are not comprehensively considered.

Therefore, the prior art has yet to be improved and improved.

Summary of the invention

In view of the above deficiencies of the prior art, it is an object of the present invention to provide a QLED device and a method of fabricating the same that achieves an efficient and stable QLED device by using a quantum dot material having a quantum well level structure.

In order to achieve the above object, the present invention adopts the following technical solutions:

A QLED device comprising a substrate, a reflective anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a transparent cathode, which are sequentially stacked, wherein the quantum dot light emitting layer adopts a quantum well level structure The quantum dot material is prepared, and the quantum dot material includes at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy composition structure in which a change in energy level width in a radial direction Or a uniform composition of uniform energy levels in the radial direction.

The QLED device further includes a hole injection layer disposed between the reflective anode and the hole transport layer.

In the QLED device, the reflective anode is an aluminum electrode or a silver electrode, and the reflective anode has a thickness of 30-800 nm.

In the QLED device, the transparent cathode is an ITO or a thin metal electrode, the ITO has a thickness of 20-300 nm, and the thin metal electrode has a thickness of 5-50 nm.

A QLED device comprising a substrate stacked in sequence, a transparent anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a reflective cathode, wherein the quantum dot light emitting layer adopts a quantum well level structure The quantum dot material is prepared, and the quantum dot material includes at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy composition structure in which a change in energy level width in a radial direction Or uniformity of the energy level width in the radial direction Component structure.

The QLED device further includes a hole injection layer disposed between the transparent anode and the hole transport layer.

In the QLED device, the transparent anode is patterned ITO.

In the QLED device, the reflective cathode is an aluminum electrode or a silver electrode, and the reflective cathode has a thickness of 30-800 nm.

A QLED device comprising a substrate, a reflective cathode, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer and a transparent anode, which are sequentially stacked, wherein the quantum dot light-emitting layer adopts a quantum well level structure The quantum dot material is prepared, and the quantum dot material includes at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy composition structure in which a change in energy level width in a radial direction Or a uniform composition of uniform energy levels in the radial direction.

The QLED device further includes a hole injection layer disposed between the hole transport layer and the transparent anode.

In the QLED device, the transparent anode is an ITO or a thin metal electrode, the ITO has a thickness of 20-300 nm, and the thin metal electrode has a thickness of 5-50 nm.

A QLED device comprising a substrate, a transparent cathode, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer and a reflective anode, which are sequentially stacked, wherein the quantum dot light-emitting layer adopts a quantum well level structure The quantum dot material is prepared, and the quantum dot material includes at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy composition structure in which a change in energy level width in a radial direction Or a uniform composition of uniform energy levels in the radial direction.

The QLED device further includes a hole injection layer disposed between the hole transport layer and the reflective anode.

In the QLED device, the transparent cathode is patterned ITO.

In the QLED device, the quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the energy level of the quantum dot structural unit adjacent in the radial direction is continuously.

In the QLED device, the quantum dot material includes at least three quantum dot structural units arranged in a radial direction, wherein the quantum dot structure at the center and the surface of the at least three quantum dot units The unit is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the energy levels of the quantum dot structural units of the graded alloy composition adjacent in the radial direction are continuous; A quantum dot structural unit between quantum dot structure units of the surface is a homogeneous composition structure.

In the QLED device, the quantum dot material comprises two types of quantum dot structural units, wherein one type of quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, Another type of quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is narrower in the radial direction, the two types of quantum dot structural units are alternately arranged in the radial direction, and in the radial direction. The energy levels of adjacent quantum dot structural units in the direction are continuous.

In the QLED device, the quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the energy levels of adjacent quantum dot structural units are discontinuous.

In the QLED device, the quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is narrower in the radial direction, and the energy levels of adjacent quantum dot structural units are discontinuous.

In the QLED device, the quantum dot material comprises two kinds of quantum dot structural units, wherein one quantum dot structural unit is a graded alloy composition structure in which the width of the outer energy level is wider in the radial direction, and another quantum The dot structural unit is a uniform component structure, and the interior of the quantum dot material includes One or more quantum dot structural units of a graded alloy composition structure, and the energy levels of the quantum dot structural units of the graded alloy composition structures adjacent in the radial direction are continuous; the outer portion of the quantum dot material includes One or more quantum dot structural units of a uniform composition structure.

In the QLED device, the quantum dot material comprises two quantum dot structural units, wherein one quantum dot structural unit has a uniform composition structure, and the other quantum dot structural unit has a larger outer energy level width in a radial direction. The wider the graded alloy composition structure, the interior of the quantum dot material includes one or more quantum dot structural units of a uniform composition structure, the outer portion of the quantum dot material including one or more graded alloy composition structures The quantum dot structural unit, and the energy levels of the quantum dot structural units of the gradual alloy composition structure adjacent in the radial direction are continuous.

In the QLED device, the quantum dot structural unit is a graded alloy component structure or a uniform alloy component structure including Group II and Group VI elements.

In the QLED device, the quantum dot structural unit comprises a 2-20 layer monoatomic layer, or the quantum dot structural unit comprises a 1-10 layer cell layer.

In the QLED device, the quantum dot material has an emission peak wavelength ranging from 400 nm to 700 nm.

In the QLED device, the half peak width of the luminescence peak of the quantum dot material is from 12 nm to 80 nm.

In the QLED device, the quantum dot light emitting layer has a thickness of 10 to 100 nm.

In the QLED device, the material of the hole injection layer is at least one of PEDOT:PSS, MoO ₃ , VO ₂ or WO ₃ .

In the QLED device, the hole injection layer has a thickness of 10 - 150 nm.

In the QLED device, the material of the hole transport layer is at least one of TFB, poly-TPD, PVK, NiO, MoO ₃ , NPB, and CBP.

In the QLED device, the hole transport layer has a thickness of 10 - 150 nm.

In the QLED device, the material of the electron transport layer is at least one of LiF, CsF, Cs ₂ CO ₃ , ZnO, and Alq ₃ .

In the QLED device, the electron transport layer has a thickness of 10 - 150 nm.

A method of fabricating the QLED device described above, comprising the steps of:

A, providing a substrate, forming a reflective anode on the substrate;

B. sequentially depositing a hole transport layer, a quantum dot light emitting layer, and an electron transport layer on the reflective anode;

C. Depositing a transparent cathode on the electron transport layer to produce a top-mounted QLED device.

In the method for preparing a QLED device, the hole transport layer, the quantum dot light-emitting layer, and the electron transport layer are deposited by a solution processing method or a vacuum evaporation method.

A method of fabricating a QLED device as described above, comprising the steps of:

A, providing a substrate, forming a transparent anode on the substrate;

B. sequentially depositing a hole transport layer, a quantum dot light emitting layer, and an electron transport layer on the transparent anode;

C. Depositing a reflective cathode on the electron transport layer to produce a positive-bottom-emitting QLED device.

A, providing a substrate, forming a reflective cathode on the substrate;

B. sequentially depositing an electron transport layer, a quantum dot light emitting layer, and a hole transport layer on the reflective cathode;

C. Depositing a transparent anode on the hole transport layer to produce a reverse top emitting QLED device.

A, providing a substrate, forming a transparent cathode on the substrate;

B. sequentially depositing an electron transport layer, a quantum dot light emitting layer and a hole transport layer on the transparent cathode;

C. Depositing a reflective anode on the hole transport layer to obtain an inverted bottom emission QLED device.

Compared with the prior art, in the QLED device and the preparation method thereof, the QLED device includes a substrate, a reflective anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer, and a transparent layer. a cathode, wherein the quantum dot light-emitting layer is prepared using a quantum dot material having a quantum well level structure, the quantum dot material including at least one quantum dot structural unit sequentially arranged in a radial direction, the quantum The point structure unit is a gradual alloy composition structure in which the energy level width changes in the radial direction or a uniform composition structure in which the energy level width is uniform in the radial direction, and can realize high-efficiency charge injection, high luminance, low driving power, and high device. Efficient QLED devices with excellent performance such as efficiency.

DRAWINGS

FIG. 1 is a schematic structural view of a QLED device according to a first embodiment of the present invention.

2 is a schematic structural view of a QLED device according to a second embodiment of the present invention.

FIG. 3 is a schematic structural view of a QLED device according to a third embodiment of the present invention.

4 is a schematic structural view of a QLED device according to a fourth embodiment of the present invention.

FIG. 5 is a schematic structural view of a QLED device according to a fifth embodiment of the present invention.

FIG. 6 is a schematic structural view of a QLED device according to a sixth embodiment of the present invention.

FIG. 7 is a schematic structural view of a QLED device according to a seventh embodiment of the present invention.

FIG. 8 is a schematic structural view of a QLED device according to an eighth embodiment of the present invention.

FIG. 9 is a graph showing the energy level structure of the specific structure 1 of the quantum dot material in the QLED device provided by the present invention.

FIG. 10 is a graph showing the energy level structure of the specific structure 2 of the quantum dot material in the QLED device provided by the present invention.

FIG. 11 is a graph showing the energy level structure of the specific structure 3 of the quantum dot material in the QLED device provided by the present invention.

12 is an energy level structure of a specific structure 4 of a quantum dot material in a QLED device provided by the present invention curve.

FIG. 13 is a graph showing the energy level structure of the specific structure 5 of the quantum dot material in the QLED device provided by the present invention.

FIG. 14 is a graph showing the energy level structure of a specific structure 6 of a quantum dot material in a QLED device provided by the present invention.

Figure 15 is a graph showing the energy level structure of a specific structure 7 of a quantum dot material in a QLED device provided by the present invention.

FIG. 16 is a schematic structural diagram of Embodiment 33 of a QLED device according to the present invention.

FIG. 17 is a schematic structural diagram of Embodiment 34 of a QLED device according to the present invention.

FIG. 18 is a schematic structural diagram of Embodiment 35 of a QLED device according to the present invention.

FIG. 19 is a schematic structural diagram of Embodiment 36 of a QLED device according to the present invention.

FIG. 20 is a schematic structural diagram of Embodiment 37 of a QLED device according to the present invention.

FIG. 21 is a schematic structural diagram of Embodiment 38 of a QLED device according to the present invention.

Figure 22 is a flow chart showing a method of fabricating a QLED device in a first embodiment of the present invention.

Figure 23 is a flow chart showing a method of fabricating a QLED device in a third embodiment of the present invention.

Figure 24 is a flow chart showing a method of fabricating a QLED device in a fifth embodiment of the present invention.

Figure 25 is a flow chart showing a method of fabricating a QLED device in a seventh embodiment of the present invention.

Figure 26 is a graph showing the electroluminescence spectrum of a QLED device in a second application embodiment provided by the present invention.

FIG. 27 is a current density-voltage curve and a luminance-voltage curve of a QLED device according to a second application embodiment provided by the present invention.

28 is an external quantum efficiency-luminance curve of a QLED device in a second application embodiment provided by the present invention.

Figure 29 is a graph showing the electroluminescence spectrum of a QLED device in a third application embodiment provided by the present invention.

30 is a current density-voltage curve of a QLED device in a third application embodiment provided by the present invention. And brightness-voltage curve.

Figure 31 is a diagram showing the external quantum efficiency-luminance curve of a QLED device in a third application embodiment provided by the present invention.

Figure 32 is a graph showing the electroluminescence spectrum of a QLED device in a fourth application embodiment provided by the present invention.

FIG. 33 is a current density-voltage curve and a luminance-voltage curve of a QLED device according to a fourth application embodiment provided by the present invention.

Figure 34 is a diagram showing the external quantum efficiency-luminance curve of a QLED device in a fourth application embodiment provided by the present invention.

detailed description

In view of the shortcomings of the prior art QLED device performance to be improved, the object of the present invention is to provide a QLED device and a method for fabricating the same, which realizes an efficient and stable QLED device by using a quantum dot material having a quantum well level structure.

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 1 , a QLED device according to a first embodiment of the present invention is a top-mounted LED QLED device, which includes a substrate 11 , a reflective anode 12 , a hole transport layer 14 , a quantum dot light-emitting layer 15 , and an electron layer which are sequentially stacked. a transport layer 16 and a transparent cathode 17, wherein the quantum dot light-emitting layer 15 is prepared using a quantum dot material having a quantum well level structure, the quantum dot material including at least one quantum arranged in a radial direction a dot structure unit, wherein the quantum dot structural unit is a graded alloy composition structure in which a change in energy level width in a radial direction or a uniform composition structure in which a width of a level in the radial direction is uniform, each of the quantum dot structural units includes 2-20 layers of monoatomic layers.

In other words, in the quantum dot material used in the top-mounted QLED device provided by the first embodiment of the present invention, each quantum dot structural unit has a single atomic layer at any position in the radial direction from the inside to the outside or More than one layer of the single atomic layer is a structure having an alloy composition.

Further, in the first embodiment of the present invention, the quantum dot structural unit contains Group II and Group VI elements. The Group II elements include, but are not limited to, Zn, Cd, Hg, Cn, etc.; the Group VI elements include, but are not limited to, O, S, Se, Te, Po, Lv, and the like. Specifically, the alloy composition of each quantum dot structural unit is Cd _x Zn _1‐x Se _y S _1‐y , where 0≤x≤1, 0≤y≤1, and x and y are not 0 and not at the same time. At the same time it is 1. It should be noted that the above situation is preferred. For a quantum dot structural unit of a graded alloy composition structure, the components thereof are all alloy components; and for a quantum component structural unit of a uniform composition structure, the components thereof It may be an alloy component or a non-alloy component, but the present invention is preferably an alloy component, that is, the uniform component structure is a uniform alloy component structure, and more preferably, it comprises a Group II and VI group element, The subsequent embodiments of the present invention are all described by taking the structure of the uniform alloy composition as an example, but it is obvious that the uniform composition of the non-alloy can also be carried out.

The radial direction herein refers to the direction outward from the center of the quantum dot material. For example, assuming that the quantum dot material of the present invention is a spherical or spherical structure, the radial direction refers to the direction of the radius, and the quantum dot material The center (or interior) refers to the center of its physical structure, and the surface (or exterior) of the quantum dot material refers to the surface of its physical structure. A more efficient and stable upright-emitting QLED device is realized by using the quantum dot material having a graded alloy composition structure. In this embodiment, the thickness of the quantum dot light-emitting layer 15 is preferably 10 - 100 nm.

The selection of the substrate 11 in the first embodiment of the present invention is not specifically limited, and a rigid glass substrate or a flexible PET substrate can be used to realize the preparation of the flexible device.

Further, referring to FIG. 2, a QLED device according to a second embodiment of the present invention is based on the top-mounted emission QLED device of the first embodiment, and a hole injection layer is disposed between the reflective anode 12 and the hole transport layer 14. 13, by adding the hole injection layer 13 to improve hole injection efficiency and mobility, balance the mobility between holes and electrons, and greatly increase the probability of carrier recombination, thereby improving QLED brightness and luminous efficiency. .

In a specific implementation, the material of the hole injection layer 13 is PEDOT:PSS, MoO ₃ , VO ₂ or WO ₃ , and the hole injection layer 13 has a thickness of 10 to 150 nm, preferably 30 to 50 nm.

The material of the hole transport layer 14 is at least one of TFB, poly-TPD, PVK, NiO, MoO ₃ , NPB, CBP, and may also be copper, iron, aluminum, nickel-doped molybdenum oxide, nickel oxide. , tungsten oxide, vanadium oxide, etc., the hole transport layer 14 has a thickness of 10 - 150 nm.

The material of the electron transport layer 16 is an inorganic material such as LiF, CsF, Cs ₂ CO ₃ , ZnO, TiO ₂ , WO ₃ , SnO ₂ , AlZnO, ZnSnO, InSnO, and the like, and Alq ₃ , TPBI ( ₁ , ₃ , 5 - 3 (N-Phenylbenzimidazole-2-yl)benzene or TAZ(3‐(4‐biphenyl)‐4‐phenyl‐5‐tert-butylphenyl-1,2,4-triazole At least one of organic materials such as NDN1 doped NET5, OXD-7, and aluminum, lithium, lanthanum, indium, lanthanum, magnesium, etc. doped inorganic oxides ZnO, TiO _{2 ,} etc. The electron transport layer 16 has a thickness of 10 - 150 nm.

Preferably, in the top-mounted QLED device provided by the first embodiment of the present invention, the reflective anode 12 is an aluminum electrode or a silver electrode, and the reflective anode 12 has a thickness of 30-800 nm, preferably 100-200 nm. The transparent cathode 17 is an ITO or a thin metal electrode. The thickness of the ITO is 20-300 nm, and the thickness of the thin metal electrode is 5-50 nm. Of course, the ITO can also adopt other transparent conductive films such as AZO and IZO. Wait.

Referring to FIG. 3, a QLED device according to a third embodiment of the present invention is a bottom-mounted QLED device, which includes a substrate 21, a transparent anode 22, a hole transport layer 24, and a quantum dot light-emitting layer 25, which are sequentially stacked. An electron transport layer 26 and a reflective cathode 27, wherein the quantum dot light-emitting layer 25 is prepared using a quantum dot material having a quantum well level structure, the quantum dot material including at least one of which is sequentially arranged in a radial direction A quantum dot structural unit is a gradual alloy composition structure in which a change in energy level width in a radial direction or a uniform composition structure in which a width in a radial direction is uniform.

In other words, in the quantum dot material used in the bottom-mounted QLED device provided by the third embodiment of the present invention, a single atomic layer at any position in the radial direction from the inside to the outside of each quantum dot structural unit. Or a structure having an alloy component within a single atomic layer range of one or more layers.

Further, in the second embodiment of the present invention, the quantum dot structural unit contains Group II and Group VI elements. The Group II elements include, but are not limited to, Zn, Cd, Hg, Cn, etc.; the Group VI elements include, but are not limited to, O, S, Se, Te, Po, Lv, and the like. Specifically, the alloy composition of each quantum dot structural unit is Cd _x Zn _1‐x Se _y S _1‐y , where 0≤x≤1, 0≤y≤1, and x and y are not 0 and not at the same time. At the same time it is 1. It should be noted that the above situation is preferred. For a quantum dot structural unit of a graded alloy composition structure, the components thereof are all alloy components; and for a quantum component structural unit of a uniform composition structure, the components thereof It may be an alloy component or a non-alloy component, but the present invention is preferably an alloy component, that is, the uniform component structure is a uniform alloy component structure, and more preferably, it comprises a Group II and VI group element, The subsequent embodiments of the present invention are all described by taking the structure of the uniform alloy composition as an example, but it is obvious that the uniform composition of the non-alloy can also be carried out.

The radial direction herein refers to the direction outward from the center of the quantum dot material. For example, assuming that the quantum dot material of the present invention is a spherical or spherical structure, the radial direction refers to the direction of the radius, and the quantum dot material The center (or interior) refers to the center of its physical structure, and the surface (or exterior) of the quantum dot material refers to the surface of its physical structure. A more efficient and stable up-bottom-emitting QLED device is realized by using the quantum dot material having a structure of a graded alloy composition. In this embodiment, the thickness of the quantum dot light-emitting layer 25 is preferably 10 - 100 nm.

The selection of the substrate 21 in the third embodiment of the present invention is not specifically limited, and a rigid glass substrate or a flexible PET substrate can be used to realize the preparation of the flexible device.

Further, referring to FIG. 4, a QLED device according to a fourth embodiment of the present invention is based on a bottom-mounted QLED device of a third embodiment, and a hole injection is disposed between the transparent anode 22 and the hole transport layer 24. Layer 23, by adding hole injection layer 23 to improve hole injection efficiency and mobility, balance the mobility between holes and electrons, greatly increase the probability of carrier recombination, thereby improving QLED brightness and luminescence effectiveness.

In a specific implementation, the material of the hole injection layer 23 is PEDOT:PSS, MoO ₃ , VO ₂ or WO ₃ , and the hole injection layer 23 has a thickness of 10 to 250 nm, preferably 30 to 50 nm.

The material of the hole transport layer 24 is at least one of TFB, poly-TPD, PVK, NiO, MoO ₃ , NPB, CBP, and may also be copper, iron, aluminum, nickel-doped molybdenum oxide, nickel oxide. , tungsten oxide, vanadium oxide, etc., the hole transport layer 24 has a thickness of 10 - 250 nm.

The material of the electron transport layer 26 is an inorganic material such as LiF, CsF, Cs ₂ CO ₃ , ZnO, TiO ₂ , WO ₃ , SnO ₂ , AlZnO, ZnSnO, InSnO, and the like, and Alq ₃ , TPBI ( ₁ , ₃ , 5 - 3 (N-Phenylbenzimidazole-2-yl)benzene or TAZ(3‐(4‐biphenyl)‐4‐phenyl‐5‐tert-butylphenyl-1,2,4-triazole At least one of organic materials such as NDN1 doped NET5, OXD-7, and aluminum, lithium, lanthanum, indium, lanthanum, magnesium, etc. doped inorganic oxides ZnO, TiO _{2 ,} etc. The electron transport layer 26 has a thickness of 10 - 250 nm.

Preferably, in the bottom-mounted QLED device provided by the third embodiment of the present invention, the transparent anode 22 is patterned ITO, the reflective cathode 27 is an aluminum electrode or a silver electrode, and the thickness of the reflective cathode 27 is 30-800 nm, preferably 100-200 nm, of course, the above patterned ITO may also use other transparent conductive films such as AZO, IZO, and the like.

Referring to FIG. 5, a QLED device according to a fifth embodiment of the present invention is an inverted top emission QLED device, which includes a substrate 31, a reflective cathode 32, an electron transport layer 34, a quantum dot light emitting layer 35, and a cavity which are sequentially stacked. a transport layer 36 and a transparent anode 37, wherein the quantum dot light-emitting layer 35 is prepared using a quantum dot material having a quantum well level structure, the quantum dot material including at least one quantum arranged in a radial direction a dot structure unit, wherein the quantum dot structure unit is a graded alloy composition structure in which a change in energy level width in a radial direction or a uniform composition structure in which a width of a level in the radial direction is uniform, and the quantum dot structure unit includes 2-20 Layer monoatomic layer.

In other words, in the quantum dot material used in the inverted top emission QLED device provided by the fifth embodiment of the present invention, each quantum dot structural unit has a single atomic layer at any position in the radial direction from the inside to the outside or More than one layer of the single atomic layer is a structure having an alloy composition.

Further, in the fifth embodiment of the present invention, the quantum dot structural unit contains Group II and Group VI elements. The Group II elements include, but are not limited to, Zn, Cd, Hg, Cn, etc.; the Group VI elements include, but are not limited to, O, S, Se, Te, Po, Lv, and the like. Specifically, the alloy composition of each quantum dot structural unit is Cd _x Zn _1‐x Se _y S _1‐y , where 0≤x≤1, 0≤y≤1, and x and y are not 0 and not at the same time. At the same time it is 1. It should be noted that the above situation is preferred. For a quantum dot structural unit of a graded alloy composition structure, the components thereof are all alloy components; and for a quantum component structural unit of a uniform composition structure, the components thereof It may be an alloy component or a non-alloy component, but the present invention is preferably an alloy component, that is, the uniform component structure is a uniform alloy component structure, and more preferably, it comprises a Group II and VI group element, The subsequent embodiments of the present invention are all described by taking the structure of the uniform alloy composition as an example, but it is obvious that the uniform composition of the non-alloy can also be carried out.

The radial direction herein refers to the direction outward from the center of the quantum dot material. For example, assuming that the quantum dot material of the present invention is a spherical or spherical structure, the radial direction refers to the direction of the radius, and the quantum dot material The center (or interior) refers to the center of its physical structure, and the surface (or exterior) of the quantum dot material refers to the surface of its physical structure. A more efficient and stable inverted top-emitting QLED device is realized by using the quantum dot material having a graded alloy composition structure. In this embodiment, the thickness of the quantum dot light-emitting layer 35 is preferably 10 to 100 nm.

The selection of the substrate 31 in the fifth embodiment of the present invention is not specifically limited, and a rigid glass substrate or a flexible PET substrate can be used to realize the preparation of the flexible device.

Further, referring to FIG. 6, a QLED device according to a sixth embodiment of the present invention is based on the inverted top emission QLED device of the fifth embodiment, and a hole injection layer is disposed between the hole transport layer 36 and the transparent anode 37. 33. By adding the hole injection layer 33 to improve hole injection efficiency and mobility, balance the mobility between holes and electrons, and greatly increase the probability of carrier recombination, thereby improving QLED brightness and luminous efficiency. .

In a specific implementation, the material of the hole injection layer 33 is PEDOT:PSS, MoO ₃ , VO ₂ or WO ₃ , and the hole injection layer 33 has a thickness of 5 to 350 nm, preferably 30 to 50 nm.

The material of the hole transport layer 36 is at least one of TFB, poly-TPD, PVK, NiO, MoO ₃ , NPB, CBP, and may also be copper, iron, aluminum, nickel-doped molybdenum oxide, nickel oxide. , tungsten oxide, vanadium oxide, etc., the hole transport layer 36 has a thickness of 10 - 350 nm.

The material of the electron transport layer 34 is an inorganic material such as LiF, CsF, Cs ₂ CO ₃ , ZnO, TiO ₂ , WO ₃ , SnO ₂ , AlZnO, ZnSnO, InSnO, and the like, and Alq ₃ , TPBI ( ₁ , ₃ , 5 - 3 (N-Phenylbenzimidazole-2-yl)benzene or TAZ(3‐(4‐biphenyl)‐4‐phenyl‐5‐tert-butylphenyl-1,2,4-triazole At least one of organic materials such as NDN1 doped NET5, OXD-7, and aluminum, lithium, lanthanum, indium, lanthanum, magnesium, etc. doped inorganic oxides ZnO, TiO _{2 ,} etc. The electron transport layer 34 has a thickness of 10 - 350 nm.

Preferably, in the inverted top emission QLED device provided by the fifth embodiment of the present invention, the reflective cathode 32 is an aluminum electrode or a silver electrode, and the reflective cathode has a thickness of 30-800 nm, preferably 100-200 nm, and the transparent The anode 37 is an ITO or a thin metal electrode. The thickness of the ITO is 20-300 nm, and the thickness of the thin metal electrode is 5-50 nm. Of course, the ITO may also use other transparent conductive films such as AZO, IZO, and the like.

Referring to FIG. 7, a QLED device according to a seventh embodiment of the present invention is an inverted bottom emission QLED device, which includes a substrate 41, a transparent cathode 42, an electron transport layer 44, a quantum dot light-emitting layer 45, and an empty layer. a hole transport layer 46 and a reflective anode 47, wherein the quantum dot light-emitting layer 45 is prepared by using a quantum dot material having a quantum well level structure, and the quantum dot material includes at least one of which is sequentially arranged in a radial direction. A quantum dot structural unit is a gradual alloy composition structure in which a change in energy level width in a radial direction or a uniform composition structure in which a width in a radial direction is uniform.

In other words, in the quantum dot material used in the anti-bottom-emitting QLED device provided by the seventh embodiment of the present invention, a single atomic layer at any position in the radial direction from the inside to the outside of each quantum dot structural unit is used. Or a structure having an alloy component within a single atomic layer range of one or more layers.

Further, in the seventh embodiment of the present invention, the quantum dot structural unit contains Group II and Group VI elements. The Group II elements include, but are not limited to, Zn, Cd, Hg, Cn, etc.; the Group VI elements include, but are not limited to, O, S, Se, Te, Po, Lv, and the like. Specifically, the alloy composition of each quantum dot structural unit is Cd _x Zn _1‐x Se _y S _1‐y , where 0≤x≤1, 0≤y≤1, and x and y are not 0 and not at the same time. At the same time it is 1. It should be noted that the above situation is preferred. For a quantum dot structural unit of a graded alloy composition structure, the components thereof are all alloy components; and for a quantum component structural unit of a uniform composition structure, the components thereof It may be an alloy component or a non-alloy component, but the present invention is preferably an alloy component, that is, the uniform component structure is a uniform alloy component structure, and more preferably, it comprises a Group II and VI group element, The subsequent embodiments of the present invention are all described by taking the structure of the uniform alloy composition as an example, but it is obvious that the uniform composition of the non-alloy can also be carried out.

The radial direction herein refers to the direction outward from the center of the quantum dot material. For example, assuming that the quantum dot material of the present invention is a spherical or spherical structure, the radial direction refers to the direction of the radius, and the quantum dot material The center (or interior) refers to the center of its physical structure, and the surface (or exterior) of the quantum dot material refers to the surface of its physical structure. A more efficient and stable inverted bottom emission QLED device is realized by using the quantum dot material having a gradual alloy composition structure. In this embodiment, the thickness of the quantum dot light-emitting layer 45 is preferably 10 - 100 nm.

The selection of the substrate 41 in the seventh embodiment of the present invention is not specifically limited, and a rigid glass substrate or a flexible PET substrate can be used to realize the preparation of the flexible device.

Further, referring to FIG. 8, a QLED device according to an eighth embodiment of the present invention is based on the inverse bottom emission QLED device of the seventh embodiment, and a hole injection is disposed between the hole transport layer 46 and the reflective anode 47. The layer 43 is formed by adding the hole injection layer 43 to improve hole injection efficiency and mobility, balance the mobility between holes and electrons, and greatly increase the probability of carrier recombination, thereby improving the luminance and luminescence of the QLED. effectiveness.

During specific embodiments, the hole injection layer 43 material is _{PEDOT: PSS, MoO 3, VO} 2 or WO _3, the thickness of the hole injection layer 43 is 5-450nm, preferably 30-50nm.

The material of the hole transport layer 46 is at least one of TFB, poly-TPD, PVK, NiO, MoO ₃ , NPB, CBP, and may also be copper, iron, aluminum, nickel-doped molybdenum oxide, nickel oxide. , tungsten oxide, vanadium oxide, etc., the hole transport layer 46 has a thickness of 10 - 450 nm.

The material of the electron transport layer 44 is an inorganic material such as LiF, CsF, Cs ₂ CO ₃ , ZnO, TiO ₂ , WO ₃ , SnO ₂ , AlZnO, ZnSnO, InSnO, and the like, and Alq ₃ , TPBI ( ₁ , ₃ , 5 - 3 (N-Phenylbenzimidazole-2-yl)benzene or TAZ(3‐(4‐biphenyl)‐4‐phenyl‐5‐tert-butylphenyl-1,2,4-triazole At least one of organic materials such as NDN1 doped NET5, OXD-7, and aluminum, lithium, lanthanum, indium, lanthanum, magnesium, etc. doped inorganic oxides ZnO, TiO _{2 ,} etc. The electron transport layer 44 has a thickness of 10 - 450 nm.

Preferably, in the inverted bottom emission QLED device provided by the seventh embodiment of the present invention, the transparent cathode 42 is a patterned ITO, and the reflective anode 47 is an aluminum electrode or a silver electrode, and the reflective anode The thickness of the pole 47 is 30-800 nm, preferably 100-200 nm. Of course, the above patterned ITO may also use other transparent conductive films such as AZO, IZO, and the like.

The structure of the quantum dot material of the present invention is described in detail below:

Specifically, as shown in FIG. 9, the present invention provides a quantum dot material having a funnel-type energy level structure, and a quantum dot structure unit alloy component located inside the quantum dot material has a corresponding energy level width smaller than a quantum located outside. The dot structure unit alloy composition corresponds to the energy level width; specifically, the quantum dot material provided by the present invention includes at least one quantum dot structure unit sequentially arranged in the radial direction, and the quantum dot structural unit has a radial direction The gradient alloy composition structure having a wider outer level width, and the energy level of the quantum dot structural unit of the graded alloy composition structure adjacent in the radial direction is continuous; the quantum shown in FIG. 9 in the subsequent embodiment The structure of the point material is referred to as a specific structure 1. In the quantum dot material of FIG. 9, the energy level width of each adjacent quantum dot structural unit has a continuous structure, that is, the energy level width of each adjacent quantum dot structural unit has a continuous change characteristic, rather than a mutant structure, that is, It is said that the synthesized components of quantum dots are also continuous, and the subsequent continuous structure is the same.

Further, in the quantum dot structural unit adjacent in the radial direction, the energy level width of the quantum dot structural unit near the center is smaller than the energy level width of the quantum dot structural unit away from the center; that is, the quantum dot material In the middle, the energy level width from the center to the surface is gradually widened, thereby forming a funnel-shaped structure in which the opening gradually becomes larger, wherein the opening gradually becomes larger, which means that the quantum dot material is in the energy level structure as shown in FIG. The energy level from the center to the surface of the quantum dot material is continuous. Meanwhile, in the quantum dot material of the present invention, the energy levels of the adjacent quantum dot structural units are continuous, that is, the synthesized components of the quantum dots also have continuously changing characteristics, which is more advantageous for achieving high performance. Luminous efficiency.

That is, the specific structure 1 of the quantum dot material is a quantum dot structure having a continuous gradual alloy composition from the inside to the outside in a radial direction; the quantum dot structure has a composition from the inside to the outside. The characteristics of continuous change in the radial direction; correspondingly, the energy level distribution also has the characteristics of continuous change from the inside to the outside in the radial direction; the quantum dot structure is composed of components and energy levels. The characteristics of continuous variation in distribution, compared with the relationship between the quantum dot core and the shell with a clear boundary, the quantum dot material of the invention not only facilitates more efficient luminous efficiency, but also satisfies the quantum device of the semiconductor device and the corresponding display technology. The comprehensive performance requirements of point materials are an ideal quantum dot luminescent material suitable for semiconductor devices and display technologies.

Further, in the quantum dot material provided in FIG. 9, the alloy composition of the point A is Cd _x0 ^A Zn _{1 - x0} ^A Se _y0 ^A S _{1 - y0} ^A , and the alloy composition of the point B is Cd _x0 ^B Zn _{1 - X0} ^B Se _y0 ^B S _1‐y0 ^B , where point A is closer to the center of the quantum dot material than point B, and the composition of points A and B satisfies: _x0 ^A ≥ _x0 ^B , _y0 ^A ≥ _y0 ^B . That is to say, for any two points A and B in the quantum dot material, and point A is closer to the center of the quantum dot material than point B, then _x0 ^A ≥ _x0 ^B , _y0 ^A ≥ _y0 ^B , that is, point A The Cd content is greater than the Cd content at point B, the Zn content at point A is less than the Zn content at point B, the Se content at point A is greater than the Se content at point B, and the S content at point A is less than the S content at point B. Thus, in the quantum dot material, a gradual structure is formed in the radial direction, and since the radial direction is outward (i.e., away from the center of the quantum dot material), the Cd and Se contents are lower, Zn and S. The higher the content, the wider the level of the energy level will be based on the characteristics of these elements.

Subsequent quantum dot material depending on the specific structure, a quantum dot structure unit when the level of the outward radial direction wider width alloy composition graded structure, its average alloy composition is preferably Cd _{_x0} Zn _{_1-x0} Se _y0 S _1‐y0 , wherein the alloy composition of point A is Cd _x0 ^A Zn _1‐x0 ^A Se _y0 ^A S _1‐y0 ^A , and the alloy composition of point B is Cd _x0 ^B Zn _1‐x0 ^B Se _y0 ^B S _1‐y0 ^B , where point A is closer to the center of the quantum dot material than point B, and the composition of points A and B satisfies: _x0 ^A > _x0 ^B , _y0 ^A > _y0 ^B . If the quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is narrower in the radial direction, the alloy composition is preferably Cd _x0 Zn _1‐x0 Se _y0 S _1‐y0 , wherein point C The alloy _composition is Cd _x0 ^C Zn _1‐x0 ^C Se _y0 ^C S _1‐y0 ^C , and the alloy composition at point ^D is Cd _x0 ^D Zn _1‐x0 ^D Se _y0 ^D S _1‐y0 ^D , where point C is relative to Point D is closer to the center of the quantum dot material, and the composition of points C and D satisfies: _x0 ^C < _x0 ^D , _y0 ^C < _y0 ^D . If the quantum dot structural unit is a uniform alloy composition structure (ie, the energy level width is uniform in the radial direction), the alloy composition is preferably Cd _x0 Zn _{1 - x0} Se _y0 S _{1 - y0} , wherein the alloy at point E The _composition is Cd _x0 ^E Zn _1‐x0 ^E Se _y0 ^E S _1‐y0 ^E , and the alloy composition at point ^F is Cd _x0 ^F Zn _1‐x0 ^F Se _y0 ^F S _1‐y0 ^F , where point E is relative to F The point is closer to the center of the quantum dot material, and the composition of points E and F satisfies: _x0 ^E = _x0 ^F , _y0 ^E = _y0 ^F .

Further, as shown in FIG. 10, the present invention further provides that the internal alloy composition has a corresponding energy level width not greater than a corresponding energy level width of the outer alloy composition component, and the quantum dot structure has at least one layer between the most central and outermost regions. a quantum dot material of a quantum dot structure unit having a uniform alloy composition structure; that is, the quantum dot material provided by the present invention includes at least three quantum dot structural units arranged in a radial direction, wherein the at least three Among the quantum dot structural units, the quantum dot structural units at the center and the surface are graded alloy composition structures having a wider outer-level width in the radial direction, and adjacent graded alloy composition structures in the radial direction The energy level of the quantum dot structural unit is continuous, and a quantum dot structural unit between the central and surface quantum dot structural units is a uniform alloy composition structure. The structure of the quantum dot material shown in FIG. 10 is referred to as a specific structure 2 in the subsequent embodiments.

Specifically, in the quantum dot material provided in FIG. 10, on the quantum dot structural unit of a uniform alloy composition structure between the central and surface quantum dot structural units, the alloy composition at any point is Cd _x1. Zn _1−x1 Se _y1 S _1‐y1 , where 0≤x1≤1, 0≤y1≤1, and x1 and y1 are not 0 at the same time and 1 at the same time, and x1 and y1 are fixed values. For example, the alloy composition at a certain point is Cd _0.5 Zn _0.5 Se _0.5 S _0.5 , and the alloy composition at another point in the radial direction should also be Cd _0.5 Zn _0.5 Se _0.5 S _0.5 ; for example, the structure of a homogeneous alloy composition A group of points in a quantum dot structure unit is divided into Cd _0.7 Zn _0.3 S, and the alloy composition of another point in the quantum dot structure unit should also be Cd _0.7 Zn _0.3 S; for example, a uniform alloy composition structure A group of points in a quantum dot structure unit is divided into CdSe, and the alloy composition of another point in the unit of the quantum dot structure should also be CdSe.

Further, in the quantum dot material provided in FIG. 10, the quantum dot structural units located at the center and the surface are both graded alloy composition structures having a wider outer-level width in the radial direction, and are adjacent in the radial direction. The energy level of the quantum dot structural unit of the graded alloy component structure is continuous; that is, in the quantum dot structural unit having the structure of the graded alloy composition, the energy level corresponding to the alloy composition at any point in the radial direction is The energy level width corresponding to the alloy composition of the adjacent and closer to the other point of the quantum dot structure center. The composition of the alloy component in the quantum dot structural unit having the structure of the graded alloy component is Cd _x2 Zn ₁ -x2 Se _y2 S _1‐y2 , where 0≤x2≤1, 0≤y2≤1, and x2 and y2 are not It is 0 at the same time and 1 at the same time. For example, the alloy composition at a certain point is Cd _0.5 Zn _0.5 Se _0.5 S _0.5 , and the alloy composition at another point is Cd _0.3 Zn _0.7 Se _0.4 S _0.6 .

Further, as shown in FIG. 11, the present invention also provides a quantum dot material having a fully graded alloy composition of a quantum well structure; that is, the quantum dot material provided by the present invention includes two types of quantum dot structural units ( A1 type and A2 type), wherein the quantum dot structure unit of the A1 type is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the quantum dot structure unit of the A2 type is the outer level in the radial direction. The narrower the width of the graded alloy composition, the two quantum dot structural units are alternately arranged in the radial direction, and the energy levels of the adjacent quantum dot structural units in the radial direction are continuous. That is, the quantum dot structure unit distribution of the quantum dot material may be: A1, A2, A1, A2, A1, ..., or A2, A1, A2, A1, A2, ..., that is, the initial quantum dot structure. The unit can be of type A1 or of type A2. In the quantum dot structure unit of the A1 type, the width of the energy level is wider toward the outside. In the quantum dot structure unit of the A2 type, the width of the energy level is narrower toward the outside, and the two energy levels are as if The form of the wavy line extends in the radial direction, and the structure of the quantum dot material shown in Fig. 11 is referred to as a specific structure 3 in the subsequent embodiment.

Further, as shown in FIG. 12, the present invention also provides a quantum dot material having an alloy composition of a quantum well structure with a sudden change in energy level. Specifically, the quantum dot structural unit is an outer level in the radial direction. The width of the gradient alloy composition is wider, and the energy levels of adjacent quantum dot structural units are discontinuous, that is, the energy level width of each adjacent quantum dot structural unit has a discontinuous change characteristic, that is, a mutation characteristic. That is to say, the alloy composition of the quantum dots is also abrupt, and the subsequent structure of the mutant structure is the same; in the subsequent embodiment, the structure of the quantum dot material shown in FIG. 12 is referred to as a specific structure 4.

Specifically, the quantum dot material described in FIG. 12 is formed by sequentially arranging a plurality of quantum dot structural units by means of abrupt changes, and the quantum dot structural units are all graded alloys having a wider outer-level width in the radial direction. Component structure. Further, in the quantum dot material, the amount close to the center The energy level width of the sub-point structural unit is smaller than the energy level width of the quantum dot structural unit away from the center. That is to say, in the quantum dot material, the energy level width from the center to the surface is gradually widened, thereby forming a funnel-shaped structure in which the intermittent opening is gradually enlarged. Of course, in the quantum dot material, It is not limited to the above manner, that is, the energy level width of the quantum dot structural unit far from the center may also be smaller than the energy level width of the quantum dot structural unit near the center. In this structure, the energy level width of the adjacent quantum dot structural unit has Interlaced overlapping places.

Further, as shown in FIG. 13, the present invention also provides another quantum dot material having an alloy composition of a quantum well structure with a sudden change in energy level. Specifically, the quantum dot structural unit is radially outward in the radial direction. The narrower the width of the graded alloy component structure, and the energy levels of adjacent quantum dot structural units are discontinuous, that is, the energy level width of each adjacent quantum dot structural unit has a discontinuous change characteristic, that is, the mutation characteristic That is to say, the alloy composition of the quantum dots is also abrupt, and the subsequent structure of the mutant structure is the same; in the subsequent embodiment, the structure of the quantum dot material shown in FIG. 13 is referred to as a specific structure 5.

Specifically, the quantum dot material described in FIG. 13 is formed by sequentially arranging a plurality of quantum dot structural units by abrupt changes, and the quantum dot structural units are all graded alloys having a narrower outer-level width in the radial direction. Component structure. Further, in the quantum dot material, the energy level width of the quantum dot structural unit near the center is larger than the energy level width of the quantum dot structural unit away from the center. That is to say, in the quantum dot material, the energy level width from the center to the surface is gradually narrowed, thereby forming a funnel-shaped structure in which the intermittent opening gradually becomes smaller. Of course, in the quantum dot material, It is not limited to the above manner, that is, the energy level width of the quantum dot structural unit far from the center may also be larger than the energy level width of the quantum dot structural unit near the center. In this structure, the energy level width of the adjacent quantum dot structural unit has Interlaced overlapping places.

Further, as shown in FIG. 14, the present invention further provides a quantum dot material, wherein an energy level width of an alloy component located inside the quantum dot material gradually increases from a center to an outer portion, and an outermost region of the quantum dot structure is uniform. The alloy component; specifically, the quantum dot material includes two quantum dot structural units (A3 type and A4 type), wherein the A3 type quantum dot structural unit is radial The gradual alloy composition structure in which the width of the outer level is wider in the direction, the quantum dot structural unit of the A4 type is a uniform alloy composition structure, and the interior of the quantum dot material includes one or more quantum structures of the gradual alloy composition. Point structure unit, and the energy level of the quantum dot structure unit of the graded alloy composition structure adjacent in the radial direction is continuous; the outer portion of the quantum dot material includes one or more quantum structures of the uniform alloy composition Point structure unit; the structure of the quantum dot material shown in FIG. 14 is referred to as a specific structure 6 in the subsequent embodiments.

Specifically, in the quantum dot material shown in FIG. 14, the distribution of the quantum dot structural unit is A3...A3A4...A4, that is, the inside of the quantum dot material is composed of A3 type quantum dot structural unit, the quantum The outside of the point material is composed of A4 type quantum dot structural units, and the number of A3 type quantum dot structural units and the number of A4 type quantum dot structural units are both greater than or equal to 1.

Further, as shown in FIG. 15, the present invention further provides another quantum dot material, wherein an alloy composition component located inside the quantum dot material has a uniform energy level width, and an alloy composition component outside the quantum dot is capable of The width of the stage is gradually increased from the center to the outside; specifically, the quantum dot material includes two kinds of quantum dot structural units (A5 type and A6 type), wherein the quantum dot structural unit of the A5 type is a uniform alloy composition structure, The quantum dot structure unit of the A6 type is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the inside of the quantum dot material includes one or more quantum dot structural units of a uniform alloy composition structure, The outer portion of the quantum dot material includes one or more quantum dot structural units of a graded alloy composition structure, and the energy levels of the quantum dot structural units of the graded alloy composition structures adjacent in the radial direction are continuous; The structure of the quantum dot material shown in Fig. 15 is referred to as a specific structure 7 in the subsequent embodiments.

Specifically, in the quantum dot material shown in FIG. 15, the distribution of the monoatomic layer is A5...A5A6...A6, that is, the inside of the quantum dot material is composed of quantum dot structural units of the A5 type, the quantum dots. The outside of the material is composed of A6 type quantum dot structural units, and the number of A5 type quantum dot structural units and the number of A6 type quantum dot structural units are both greater than or equal to 1.

Further, the quantum dot structural unit provided by the present invention comprises a 2-20 layer monoatomic layer. Preferably, the quantum dot structural unit comprises 2-5 monoatomic layers, and the preferred number of layers can ensure that the quantum dots achieve good luminescence quantum yield and efficient charge injection efficiency.

Further, the quantum dot light emitting unit comprises 1-10 layer cell layers, preferably 2-5 layer cell layers; the cell layer is the smallest structural unit, that is, the cell layer of each layer has an alloy composition of Fixed, that is, each cell layer has the same lattice parameter and element, and each quantum dot structural unit is a closed cell surface formed by connecting the cell layers, and the energy level width between adjacent cell layers has Continuous structure or mutant structure.

The quantum dot material of the above structure can achieve a luminescence quantum yield ranging from 1% to 100%, and a preferred luminescence quantum yield range of 30% to 100%, and the quantum is guaranteed within a preferred range of luminescence quantum yield. Good applicability of the point.

Wherein, the quantum dot material has an emission peak wavelength ranging from 400 nm to 700 nm.

The quantum dot material of the above structure can realize the luminescence peak wavelength range of 400 nm to 700 nm, and the preferred luminescence peak wavelength range is 430 nm to 660 nm, and the preferred quantum dot luminescence peak wavelength range can ensure the quantum dot material. A luminescence quantum yield of greater than 30% is achieved in this range.

Further, in the present invention, the half peak width of the luminescence peak of the quantum dot material is from 12 nm to 80 nm.

The quantum dot material used in the present invention has the following beneficial effects: firstly, it helps to minimize the lattice tension between quantum dot crystals of different alloy compositions and alleviate lattice mismatch, thereby reducing the formation of interface defects. , improve the luminous efficiency of quantum dots. Secondly, the energy level structure formed by the quantum dot material provided by the invention is more favorable for the effective binding of the electron cloud in the quantum dot, and greatly reduces the probability of diffusion of the surface of the electron cloud vector sub-point, thereby greatly suppressing the quantum dot without The Auger recombination loss of the radiation transition reduces the quantum dot flicker and improves the luminous efficiency of the quantum dot. Thirdly, the energy level structure formed by the quantum dot material provided by the invention is more favorable for improving the injection efficiency and transmission efficiency of the quantum dot light-emitting layer charge in the QLED device; and at the same time, the charge accumulation can be effectively avoided. And the resulting exciton quenching. Fourth, the easily controllable multi-level structure formed by the quantum dot material provided by the present invention can fully satisfy and match the energy level structure of other functional layers in the device, so as to achieve matching of the overall energy level structure of the device, thereby contributing to Achieve efficient QLED devices.

The invention also provides a preparation method of the quantum dot material as described above, which comprises the steps of:

Synthesizing the first compound at a predetermined position;

Forming a second compound on the surface of the first compound, the first compound being the same as or different from the alloy composition of the second compound;

A cation exchange reaction occurs between the first compound and the second compound to form a quantum dot material, and the luminescence peak wavelength of the quantum dot exhibits one or more of blue shift, red shift, and constant.

The preparation method of the invention combines the quantum dot SILAR synthesis method with the quantum dot one-step synthesis method to generate quantum dots, specifically, the quantum dot SILAR synthesis method is used to precisely control the quantum dot layer-by-layer growth and the quantum dot one-step synthesis method is used to form the graded component transition shell. That is, two thin layers of a compound having the same or different alloy compositions are successively formed at predetermined positions, and the alloy component distribution at a predetermined position is achieved by causing a cation exchange reaction between the two layers of compounds. Repeating the above process can continuously achieve the distribution of the alloy composition at a predetermined position in the radial direction.

The first compound and the second compound may be binary or binary compounds.

Further, when the wavelength of the luminescence peak of the quantum dot is blue-shifted, the luminescence peak shifts toward the short-wave direction, and the energy level width is widened; when the luminescence peak wavelength of the quantum dot appears red-shifted, it represents the luminescence peak toward the long-wave direction. When moving, the energy level width is narrowed; when the wavelength of the luminescence peak of the quantum dot is constant, the width of the energy level is unchanged.

The cation precursor of the first compound and/or the second compound includes: a precursor of Zn, and the precursor of the Zn is dimethyl Zinc, diethyl zinc (diethyl Zinc) , Zinc acetate, Zinc acetylacetonate, Zinc iodide, Zinc bromide, Zinc chloride, Zinc fluoride, Zinc carbonate (Zinc carbonate), Zinc cyanide, Zinc nitrate, Zinc oxide, Zinc peroxide, Zinc perchlorate, Zinc sulfate, Zinc oleate or Zinc stearate At least one, but not limited to.

The cationic precursor of the first compound and/or the second compound includes a precursor of Cd, and the precursor of the Cd is dimethyl cadmium, diethyl cadmium, Cadmium acetate, cadmium acetylacetonate, cadmium iodide, cadmium bromide, cadmium chloride, cadmium fluoride, cadmium carbonate Cadmium carbonate), cadmium nitrate, cadmium oxide, cadmium perchlorate, cadmium phosphide, cadmium sulfate, cadmium oleate or hard At least one of cadmium stearate and the like, but is not limited thereto.

The anion precursor of the first compound and/or the second compound includes a precursor of Se, such as a compound formed by any combination of Se and some organic substances, specifically Se-TOP (selenium-trioctylphosphine) , Se‐TBP (selenium-tributylphosphine), Se‐TPP (selenium‐triphenylphosphine), Se‐ODE (selenium‐1‐octadecene), Se‐OA (selenium‐oleic acid), Se‐ODA (selenium‐octadecylamine), Se At least one of -TOA (selenium-trioctylamine), Se-ODPA (selenium-octadecylphosphonic acid), or Se-OLA (selenium-oleylamine), etc., but is not limited thereto.

The anion precursor of the first compound and/or the second compound includes a precursor of S, such as a compound formed by any combination of S and some organic substances, specifically S-TOP (sulfur-trioctylphosphine), S ‐TBP(sulfur-tributylphosphine), S‐TPP(sulfur‐triphenylphosphine), S‐ODE(sulfur‐1‐octadecene), S‐OA(sulfur‐oleic acid), S‐ODA(sulfur‐octadecylamine), S‐TOA At least one of (sulfur-trioctylamine), S-ODPA (sulfur-octadecylphosphonic acid) or S-OLA (sulfur-oleylamine), etc., but is not limited thereto; the precursor of the S is an alkylthiol (alkyl thiol) The alkyl sulfur The alcohol is hexanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol or mercaptopropylsilane. At least one of the foregoing, but is not limited thereto.

The anion precursor of the first compound and/or the second compound further includes a precursor of Te, and the precursor of the Te is Te‐TOP, Te‐TBP, Te‐TPP, Te‐ODE, Te At least one of ‐OA, Te‐ODA, Te‐TOA, Te‐ODPA, or Te‐OLA.

In the production method of the present invention, the cation exchange reaction is carried out under the conditions of a heating reaction, for example, a heating temperature of between 100 ° C and 400 ° C, and a preferred heating temperature of between 150 ° C and 380 ° C. The heating time is between 2 s and 24 h, and the preferred heating time is between 5 min and 4 h.

The above cationic precursor and anionic precursor may be determined according to the final nanocrystal composition to determine one or more of them: for example, when it is required to synthesize a nanocrystal of Cd _x Zn _1‐x Se _y S _1‐y , Cd is required. Precursor, precursor of Zn, precursor of Se, precursor of S; if it is necessary to synthesize nanocrystals of Cd _x Zn _{1 -x} S, a precursor of Cd, a precursor of Zn, and a precursor of S are required; such as the need synthetic Cd _{_x} Zn _{_1-x} Se nanocrystals, it is necessary precursors of Cd, Zn precursor precursor, Se in.

The higher the heating temperature, the faster the rate of cation exchange reaction, the greater the thickness range and degree of exchange of cation exchange, but the thickness and extent range will gradually reach relative saturation; similarly, the longer the heating time, the thickness of cation exchange The extent and degree of exchange are also greater, but the thickness and extent range will gradually reach a relative saturation level. The thickness range and extent of cation exchange directly determines the distribution of the graded alloy composition formed. The distribution of the graded alloy composition formed by cation exchange is also determined by the thickness of the binary or multicomponent compound nanocrystals formed by each.

When forming each layer of the compound, the molar ratio of the cationic precursor to the anionic precursor may be from 100:1 to 1:50 (specifically, the molar ratio of the cation to the anion), for example, when forming the first layer of the compound, the cationic precursor The molar ratio to the anion precursor is from 100:1 to 1:50; in forming the second layer compound, the molar ratio of the cationic precursor to the anionic precursor is from 100:1 to 1:50, and the preferred ratio is 20:1. By 1:10, the preferred molar ratio of cationic precursor to anionic precursor For example, it is possible to ensure that the reaction rate is within an easily controllable range.

The quantum dot material prepared by the above preparation method has a luminescence peak wavelength ranging from 400 nm to 700 nm, and a preferred luminescence peak wavelength range is 430 nm to 660 nm, and a preferred quantum dot luminescence peak wavelength range can ensure quantum dots here. A luminescence quantum yield of greater than 30% is achieved in the range.

The quantum dot material prepared by the above preparation method has a luminescence quantum yield ranging from 1% to 100%, and a preferred luminescence quantum yield range is from 30% to 100%, and a preferred quantum dot yield is ensured in the range of luminescence quantum yield. Application.

In addition to preparing the quantum dot material of the present invention according to the above preparation method, the present invention also provides a method for preparing a quantum dot material as described above, which comprises the steps of:

Adding one or more cationic precursors at predetermined positions in the radial direction; simultaneously adding one or more anionic precursors under certain conditions to react the cationic precursor with the anionic precursor to form a quantum dot material And the luminescence peak wavelength of the quantum dot material exhibits one or more of blue shift, red shift, and invariance during the reaction, thereby achieving distribution of the alloy composition at a predetermined position.

The difference between the above method and the former method is that the former one forms two layers of compounds one after another, and then a cation exchange reaction occurs to realize the distribution of the alloy components required by the present invention, and the latter method is directly controlled. A cationic precursor and an anionic precursor of the desired synthetic alloy component are added at predetermined positions to react to form a quantum dot material, thereby achieving the desired alloy component distribution of the present invention. In the latter method, the reaction principle is that the highly reactive cationic precursor and the anionic precursor react first, the reactive precursor with low reactivity and the anionic precursor react, and during the reaction, different cations undergo cations. The reaction is exchanged to achieve the desired alloy component distribution of the present invention. The types of cationic precursors and anionic precursors are detailed in the foregoing methods. As for the reaction temperature, reaction time and ratio, etc., depending on the specific needs The synthesized quantum dot materials vary, and are substantially the same as the former method described above, and will be described later in the specific examples.

The QLED device provided by the present invention and the quantum dot material used therein will be further described below by way of specific examples.

Example 1: Preparation of CdZnSeS/CdZnSeS quantum dots

First, a precursor of a cationic Cd, a precursor of a cationic Zn, a precursor of an anion Se, and a precursor of an anion S are injected into a reaction system to form a Cd _y Zn _1‐y Se _b S _1‐b layer (where 0≤y) ≤1,0≤b≤1); the precursor of the cationic Cd, the precursor of the cationic Zn, the precursor of the anion Se, and the precursor of the anion S are continuously injected into the reaction system, in the above Cd _y Zn _1‐y Se _{b The} surface of the S _{1 - b} layer forms a layer of Cd _z Zn _1‐z Se _c S _1‐c (where 0≤z≤1, and z is not equal to y, 0≤c≤1); at a certain heating temperature and heating time Under the same reaction conditions, the exchange of Cd and Zn ions in the inner and outer nanocrystals (ie, the above two layers of compounds) occurs; the probability of migration due to the cation migration distance is limited and the migration distance is farther, so it will be in Cd. A gradual alloy composition distribution of Cd content and Zn content near the interface between the _y Zn _1‐y Se _b S _1‐b layer and the Cd _z Zn _1‐z Se _c S _1‐c layer, ie Cd _x Zn _1‐x Se _a S _1‐a , where 0≤x≤1, 0≤a≤1.

Example 2: Preparation based on CdZnS/CdZnS quantum dots

First, the precursor of the cationic Cd, the precursor of the cationic Zn, and the precursor of the anion S are injected into the reaction system to form a Cd _y Zn _{1 -y} S layer (where 0 _{≤ y ≤} ₁ ); the precursor of the cationic Cd is continued. The precursor of the bulk, cationic Zn and the precursor of the anion S are injected into the reaction system to form a Cd _z Zn _1‐z S layer on the surface of the above Cd _y Zn _1‐y S layer (where 0≤z≤1, and z Not equal to y); under certain reaction conditions such as heating temperature and heating time, the exchange of Cd and Zn ions in the inner and outer nanocrystals (ie, the above two layers of compounds) occurs; due to the limited migration distance of the cations and the further migration The smaller the probability of migration, the gradient alloy composition distribution of Cd content and Zn content near the interface between Cd _y Zn _1‐y S layer and Cd _z Zn _1‐z S layer, ie Cd _x Zn _{1 ‐x} S, where 0≤x≤1.

Example 3: Preparation of CdZnSe/CdZnSe quantum dots

First, the precursor of the cationic Cd, the precursor of the cationic Zn, and the precursor of the anion Se are injected into the reaction system to form a layer of Cd _y Zn _1‐y Se (where 0 _{≤ y ≤} ₁ ); the precursor of the cation Cd is continued. The precursor of the cationic Zn and the precursor of the anion Se are injected into the reaction system to form a Cd _z Zn _1‐z Se layer on the surface of the above Cd _y Zn _1‐y Se layer (where 0≤z≤1, and z does not Equivalent to y); under certain reaction conditions such as heating temperature and heating time, the exchange of Cd and Zn ions in the inner and outer nanocrystals occurs; the probability of migration due to the limited migration distance of the cation and the farther migration distance is smaller. graded alloy composition, therefore the content of Cd and Zn are formed in the vicinity of the interface Cd _{_y} Zn _{_1-y} Se layer and Cd _{_z} Zn _{_1-z} Se distribution layer, i.e., Cd _{_x} Zn _{_1-x} Se, wherein 0≤x ≤1.

Example 4: Preparation based on CdS/ZnS quantum dots

First, the precursor of the cationic Cd and the precursor of the anion S are injected into the reaction system to form a CdS layer; the precursor of the cationic Zn and the precursor of the anion S are continuously injected into the reaction system to form on the surface of the CdS layer. ZnS layer; under certain reaction conditions such as heating temperature and heating time, the Zn cation of the outer layer will gradually migrate to the inner layer and undergo cation exchange reaction with Cd cation, that is, Cd ion migrates to the outer layer, and Cd and Zn occur. Ion exchange; the migration distance of the cation is limited and the migration distance of the migration distance is smaller, so the Cd content is gradually decreased along the radial direction and the Zn content is formed near the interface between the CdS layer and the ZnS layer. A graded alloy composition distribution that gradually increases outward in the radial direction, that is, Cd _x Zn _{1 - x} S, where 0 ≤ x ≤ 1 and x decreases monotonically from 1 to 0 from the inside to the outside (radial direction).

Example 5: Preparation based on CdSe/ZnSe quantum dots

The precursor of the cationic Cd and the precursor of the anion Se are first injected into the reaction system to form a CdSe layer; the precursor of the cationic Zn and the precursor of the anion Se are continuously injected into the reaction system to form ZnSe on the surface of the CdSe layer. Under certain reaction conditions such as heating temperature and heating time, the Zn cation of the outer layer gradually migrates to the inner layer and undergoes cation exchange reaction with Cd cations, that is, Cd ions migrate to the outer layer, and Cd and Zn ions occur. The interchangeability of the cations due to the limited migration distance of the cations and the migration distance of the migration distance is smaller. Therefore, the Cd content near the interface between the CdSe layer and the ZnSe layer gradually decreases along the radial direction, and the Zn content decreases. The distribution of the graded alloy composition gradually increasing radially outward, that is, Cd _x Zn _{1 - x} Se, where 0 ≤ x ≤ 1 and x is monotonously decreasing from 1 to 0 from the inside to the outside (radial direction).

Example 6: Preparation based on CdSeS/ZnSeS quantum dots

First, the precursor of the cationic Cd, the precursor of the anion Se, and the precursor of the anion S are injected into the reaction system to form a CdSe _b S _{1 -b} layer (where 0 ≤ b ≤ 1); the precursor of the cationic Zn is continued, The precursor of the anion Se and the precursor of the anion S are injected into the reaction system to form a layer of ZnSe _c S _{1 -c on the} surface of the above CdSe _b S _{1 -b} layer (where 0 ≤ _c ≤ 1); at a certain heating temperature Under the reaction conditions such as heating time, the Zn cation of the outer layer gradually migrates to the inner layer and undergoes cation exchange reaction with the Cd cation, that is, the Cd ion migrates to the outer layer, and the exchange of Cd and Zn ions occurs; The migration distance is limited and the migration distance of the migration distance is smaller. Therefore, the Cd content in the vicinity of the interface between the CdSe _b S _1‐b layer and the ZnSe _c S _1‐c layer gradually decreases along the radial direction. The distribution of the grading alloy composition with increasing Zn content along the radial direction, ie Cd _x Zn _1‐x Se _a S _1‐a , where 0≤x≤1 and x monotonous from the inside to the outside (radial direction) from 1 Decrement to 0, 0 ≤ a ≤ 1.

Example 7: Preparation based on ZnS/CdS quantum dots

The precursor of the cationic Zn and the precursor of the anion S are first injected into the reaction system to form a ZnS layer; the precursor of the cationic Cd and the precursor of the anion S are continuously injected into the reaction system to form a CdS on the surface of the ZnS layer. Under certain reaction conditions such as heating temperature and heating time, the Cd cation of the outer layer gradually migrates to the inner layer and undergoes cation exchange reaction with the Zn cation, that is, Zn ions migrate to the outer layer, and Cd and Zn ions occur. The interchangeability of the cations due to the limited migration distance of the cations and the migration distance of the longer distances, so that the Zn content in the vicinity of the interface between the ZnS layer and the CdS layer gradually decreases along the radial direction, and the Cd content decreases. The distribution of the graded alloy composition gradually increasing radially outward, that is, Cd _x Zn _{1 - x} S, where 0 ≤ x ≤ 1 and x monotonously increases from 0 to 1 from the inside to the outside (radial direction).

Example 8: Preparation based on ZnSe/CdSe quantum dots

First, a precursor of a cationic Zn and a precursor of an anion Se are injected into the reaction system to form a ZnSe layer; and a precursor of a cationic Cd and a precursor of an anion Se are continuously injected into the reaction system to form a CdSe on the surface of the ZnSe layer. Under certain reaction conditions such as heating temperature and heating time, the Cd cation of the outer layer gradually migrates to the inner layer and undergoes cation exchange reaction with the Zn cation, that is, Zn ions migrate to the outer layer, and Cd and Zn ions occur. The interchangeability of the cations due to the limited migration distance of the cations and the migration distance of the migration distance is smaller. Therefore, the Zn content near the interface between the ZnSe layer and the CdSe layer gradually decreases along the radial direction, and the Cd content decreases. The distribution of the graded alloy composition gradually increasing radially outward, that is, Cd _x Zn _{1 - x} Se, where 0 ≤ x ≤ 1 and x monotonically increases from 0 to 1 from the inside to the outside (radial direction).

Example 9: Preparation based on ZnSeS/CdSeS quantum dots

First, a precursor of a cationic Zn, a precursor of an anion Se, and a precursor of an anion S are first injected into a reaction system to form a ZnSe _b S _{1 -b} layer (where 0 ≤ b ≤ 1); the precursor of the cationic Cd is continued, The precursor of the anion Se and the precursor of the anion S are injected into the reaction system to form a layer of CdSe _c S _{1-c on the} surface of the above ZnSebS1‐b layer (where 0≤c≤1); at a certain heating temperature and heating time Under the same reaction conditions, the Cd cation of the outer layer will gradually migrate to the inner layer and undergo cation exchange reaction with the Zn cation, that is, the Zn ion migrates to the outer layer, and the exchange of Cd and Zn ions occurs; the migration distance of the cation is limited. The farther the migration distance is less likely to migrate, the Zn content in the vicinity of the interface between the ZnSe _b S _1‐b layer and the CdSe _c S _1‐c layer will gradually decrease along the radial direction, and the Cd content will decrease. The distribution of the graded alloy composition gradually increasing radially outward, namely Cd _x Zn _1‐x Se _a S _1‐a , where 0≤x≤1 and x monotonically increasing from 0 to 1,0≤a≤ from the inside to the outside 1.

Example 10: Preparation of Blue Quantum Dots with Specific Structure 1

Preparation of cadmium oleate and zinc oleate precursor: 1 mmol of cadmium oxide (CdO), 9 mmol of zinc acetate [Zn(acet) ₂ ], 8 mL of oleic acid (Oleic acid), and 15 mL of octadecene (1 -Octadecene) were placed. In a 100 mL three-necked flask, vacuum degassing was carried out at 80 ° C for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

2 mmol of sulfur powder (Sulfur powder) was dissolved in 3 mL of octadecene (1 - Octadecene) to obtain a thiooctadecene precursor.

6 mmol of sulfur powder (Sulfur powder) was dissolved in 3 mL of Trioctylphosphine to obtain a trioctylphosphine sulfide precursor.

0.6 mmol of cadmium oxide (CdO), 0.6 mL of oleic acid (Oleic acid) and 5.4 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask, and heated under reflux in a nitrogen atmosphere at 250 ° C for 120 min to obtain a transparent oleic acid. Cadmium precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system. After 10 minutes of reaction, the trioctylphosphine sulfide precursor and cadmium oleate were sulfided. The precursor was added dropwise to the reaction system at a rate of 3 mL/h and 10 mL/h, respectively. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and then purified by centrifugation to obtain a blue quantum dot (Cd _x Zn _{1 - x} S) having a specific structure 1.

Example 21: Preparation of Green Quantum Dots with Specific Structure 1

Preparation of cadmium oleate and zinc oleate precursor: 0.4 mmol of cadmium oxide (CdO), 8 mmol of zinc acetate [Zn(acet) ₂ ], and 10 mL of oleic acid (Oleic acid) were placed in a 100 mL three-necked flask at 80 ° C. Vacuum degassing for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

2 mmol of Selenium powder and 4 mmol of sulfur powder were dissolved in 4 mL of Tricylphosphine to obtain a trioctylphosphine selenide-trioctylphosphine sulfide precursor.

2 mmol of sulfur powder (Sulfur powder) was dissolved in 2 mL of Trioctylphosphine to obtain a trioctylphosphine sulfide precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine trisulfide sulfide trioctylphosphine precursor was rapidly injected into the reaction system to form Cd _x Zn _1‐x. Se _y S _1‐y , after reacting for 10 min, 2 mL of the trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 8 mL/h until the precursor was injected. After the reaction is completed, after the reaction solution is cooled to room temperature, the product is repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green quantum dot having a specific structure (Cd _x Zn _{1 -x} Se _y S _1‐y /Cd _z Zn _1‐z S), where the front of "/" represents the composition of the interior of the prepared green quantum dot, and the end of "/" represents the composition outside the prepared green quantum dot, and "/" It is not the obvious boundary, but the structure that changes from the inside to the outside. The subsequent quantum dot representation has the same meaning.

Example 12: Preparation of red quantum dots with specific structure 1

Preparation of cadmium oleate and zinc oleate precursor: 0.8 mmol of cadmium oxide (CdO), 12 mmol of zinc acetate [Zn(acet) ₂ ], and 14 mL of oleic acid (Oleic acid) were placed in a 100 mL three-necked flask at 80 ° C. Vacuum degassing for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

2 mmol of Selenium powder was placed in 4 mL of Trioctylphosphine to obtain a trioctylphosphine selenide precursor.

0.2 mmol of Selenium powder and 0.6 mmol of sulfur powder (Sulfur powder) were dissolved in 2 mL of Trioctylphosphine to obtain a trioctylphosphine selenide-trioctylphosphine sulfide precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to form Cd _x Zn _{1 -x} Se. After 10 minutes of reaction, 2 mL of a trioctylphosphine selenide-trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 4 mL/h. After the reaction is completed, after the reaction solution is cooled to room temperature, the product is repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red fluorescent quantum dot having a specific structure 1 (Cd _x Zn _1‐x Se _y S _{1‐ y} /CdzZn _1‐z S).

Example 13: Effect of cadmium oleate injection rate on blue quantum dot synthesis with specific structure 1

On the basis of the embodiment 10, by adjusting the injection rate of cadmium oleate, the slope of the gradient change of the quantum dot component can be controlled, thereby affecting the energy level structure, and finally realizing the regulation of the quantum dot emission wavelength.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form Cd _x Zn _{1 -x} S. After 10 minutes of reaction, the sulfide was vulcanized. The trioctylphosphine precursor was added dropwise to the reaction system at a rate of 3 mL/h, while the cadmium oleate precursor was added dropwise to the reaction system at different injection rates. After the completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a blue quantum dot having an energy level structure 1 (Cd _x Zn _{1 -x} S/Cd _y Zn _1‐y S).

Based on the same quantum dot center (alloy quantum dot luminescence peak 447nm) and the injection rate of different cadmium oleate precursors, the list of quantum dot emission wavelength modulation is as follows:

油酸镉注入速率(mmol/h)Cadmium oleate injection rate (mmol/h)	发光波长(nm)Luminous wavelength (nm)
0.50.5	449449
0.750.75	451451
11	453453
1.251.25	455455
1.51.5	456456

Example 14: Effect of cadmium oleate injection on the synthesis of blue quantum dots with specific structure 1

On the basis of Example 10 and Example 13, by adjusting the amount of cadmium oleate precursor injected, It is possible to control the interval of the gradient change of the composition of the quantum dot, thereby affecting the change of the energy level structure, and finally realizing the regulation of the wavelength of the quantum dot. Based on the same quantum dot center (alloy quantum dot luminescence peak 447 nm) and the injection amount of different oleic acid cadmium precursors (1 mmol/h at the same injection rate), the quantum dot emission wavelength modulation is listed below.

油酸镉注入量(mmol)Cadmium oleate injection amount (mmol)	发光波长(nm)Luminous wavelength (nm)
0.40.4	449449
0.50.5	451451
0.60.6	453453
0.80.8	454454
1.01.0	455455

Example 15: Preparation of Blue Quantum Dots with Concrete Structure 2

Preparation of cadmium oleate and zinc oleate precursor: 1 mmol of cadmium oxide (CdO), 9 mmol of zinc acetate [Zn(acet) ₂ ], 8 mL of oleic acid (Oleic acid) and 15 mL of octadecene (1 -Octadecene) were placed in 100 mL In a three-necked flask, vacuum degassing was carried out at 80 ° C for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form Cd _x Zn _{1 -x} S. After 10 minutes of reaction, the reaction was carried out. The temperature of the system was lowered to 280 ° C, and then 2 mL of a trioctylphosphine sulfide precursor and 6 mL of a cadmium oleate precursor were simultaneously injected into the reaction system at a rate of 3 mL/h and 10 mL/h, respectively. After 40 min of injection, the temperature of the reaction system was raised to 310 ° C, and 1 mL of the trioctylphosphine sulfide precursor was injected into the reaction system at a rate of 3 mL/h. After the reaction was completed, the reaction solution was cooled to room temperature, and then toluene and no. The product was repeatedly dissolved and precipitated by water methanol, and purified by centrifugation to obtain a blue quantum dot of the specific structure 2.

Example 16: Preparation of green quantum dots with specific structure 2

Preparation of cadmium oleate and zinc oleate precursor: 0.4 mmol of cadmium oxide (CdO), 8 mmol of zinc acetate [Zn(acet) 2], 10 mL of oleic acid (Oleic acid) and 20 mL of octadecene (1 -Octadecene) were placed. In a 100 mL three-necked flask, vacuum degassing was carried out at 80 ° C for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

2 mmol of Selenium powder and 4 mmol of sulfur powder were dissolved in 4 mL of Trioctylphosphine to obtain a trioctylphosphine selenide-trioctylphosphine sulfide precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine trisulfide sulfide trioctylphosphine precursor was rapidly injected into the reaction system to form Cd _x Zn _1‐x. Se _y S _1‐y , after reacting for 10 min, the temperature of the reaction system was lowered to 280 ° C, and then 1.2 mL of the trioctylphosphine sulfide precursor and 6 mL of the cadmium oleate precursor were respectively at a rate of 2 mL/h and 10 mL/h. Inject into the reaction system until the precursor is injected. The temperature of the reaction system was raised to 310 ° C, and 0.8 mL of a trioctylphosphine sulfide precursor was injected into the reaction system at a rate of 2 mL/h. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green quantum dot having a specific structure 2.

Example 17: Preparation of red quantum dots with specific structure 2

Preparation of cadmium oleate and zinc oleate precursor: 0.8 mmol of cadmium oxide (CdO), 12 mmol of zinc acetate [Zn(acet) ₂ ], 14 mL of oleic acid (Oleic acid) and 20 mL of octadecene (1 -Octadecene) were placed. In a 100 mL three-necked flask, vacuum degassing was carried out at 80 ° C for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

0.3 mmol of cadmium oxide (CdO), 0.3 mL of oleic acid (Oleic acid) and 2.7 mL of octadecene (1 -Octadecene) were placed in a 50 mL three-necked flask, and heated under reflux in a nitrogen atmosphere at 250 ° C for 120 min to obtain a transparent oleic acid. Cadmium precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to form Cd _x Zn _{1 -x} Se. After 10 minutes of reaction, The temperature of the reaction system was lowered to 280 ° C, and then 1 mL of a trioctylphosphine sulfide-trioctylphosphine sulfide precursor and 3 mL of a cadmium oleate precursor were injected into the reaction system at a rate of 2 mL/h and 6 mL/h, respectively. The temperature of the reaction system was raised to 310 ° C, and 1 mL of a trioctylphosphine selenide-trioctylphosphine sulfide precursor was injected into the reaction system at a rate of 4 mL/h. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red quantum dot having a specific structure 2.

Example 18: Preparation of blue quantum dots with specific structure 3

Dissolve 2mmol of sulfur powder (Sulfur powder) in 3mL of octadecene (1‐Octadecene) In the middle, a thiooctadecene precursor is obtained.

0.2 mmol of Selenium powder was dissolved in 1 mL of Trioctylphosphine to obtain a trioctylphosphine selenide precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form Cd _x Zn _{1 -x} S. After 10 minutes of reaction, the oil was oiled. The cadmium acid precursor and the trioctylphosphine sulfide precursor were continuously injected into the reaction system at a rate of 0.6 mmol/h and 4 mmol/h, respectively, for 20 min. Subsequently, the cadmium oleate precursor, the trioctylphosphine sulfide precursor and the trioctylphosphine selenide precursor were successively injected into the reaction system at a rate of 0.4 mmol/h, 0.6 mmol/h and 0.2 mmol/h, respectively, for 1 h. After the reaction was completed, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a blue quantum dot (CdZnS/CdZnS/) having a quantum well level structure (specific structure 3). CdZnSeS ₃ ).

Example 19: Preparation of Green Quantum Dots with Specific Structure 3

Preparation of cadmium oleate and zinc oleate precursor: 0.4 mmol of cadmium oxide (CdO), 6 mmol of zinc acetate [Zn(acet) ₂ ], 10 mL of oleic acid (Oleic acid) and 20 mL of octadecene (1 -Octadecene) were placed. In a 100 mL three-necked flask, vacuum degassing was carried out at 80 ° C for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

0.4 mmol of Selenium powder and 4 mmol of sulfur powder (Sulfur powder) were dissolved in 4 mL of Trioctylphosphine to obtain trioctylphosphine selenide-trioctylphosphine sulfide precursor 1.

0.1 mmol of Selenium powder, 0.3 mmol of sulfur powder (Sulfur powder) was dissolved in 2 mL of Trioctylphosphine to obtain trioctylphosphine sulfide-vulcanization. Trioctylphosphine precursor 2.

0.8 mmol of sulfur powder (Sulfur powder) and 0.8 mmol of Selenium powder were dissolved in 3 mL of Trioctylphosphine to obtain trioctylphosphine selenide-trioctylphosphine sulfide precursor 3.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under nitrogen atmosphere, and the trioctylphosphine trisulfide sulfide trioctylphosphine precursor 1 was quickly injected into the reaction system to form Cd _x Zn _{1‐ x} SeyS _{1 -y} , after reacting for 5 min, 2 mL of trioctylphosphine selenide-trioctylphosphine sulfide precursor 2 was added dropwise to the reaction system at a rate of 6 mL/h. Subsequently, 3 mL of trioctylphosphine selenide-

trioctylphosphine sulfide precursor

3 and 6 mL of the cadmium oleate precursor were continuously added dropwise to the reaction system at a rate of 3 mL/h and 6 mL/h, respectively. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green quantum dot (CdZn ₃ SeS ₃ /Zn ₄ SeS ₃ /Cd ₃ having a specific structure 3). Zn ₅ Se ₄ S ₄ ).

Example 20: Preparation of red quantum dots with specific structure 3

0.9mmol cadmium oxide (CdO), 0.9mL oleic acid (Oleic acid) and 8.1mL octadecene (1‐Octadecene) was placed in a 100 mL three-necked flask and heated under reflux in a nitrogen atmosphere at 250 ° C for 120 min to obtain a transparent cadmium oleate precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to form Cd _x Zn _{1 -x} Se. After 10 minutes of reaction, 2 mL of a trioctylphosphine selenide-trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 2 mL/h. When injected for 30 min, 3 mL of a cadmium oleate precursor was simultaneously added dropwise to the reaction system at a rate of 6 mL/h. After the reaction was completed, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red quantum dot (Cd _x Zn _{1 -x} Se/ZnSe _y S ₁ having a specific structure 3). _‐y /Cd _z Zn _1‐z SeS).

Example 21: Preparation of Blue Quantum Dots with Concrete Structure 4

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form CdxZn1‐xS. After 10 minutes of reaction, the cadmium oleate precursor was prepared. And the trioctylphosphine precursor of selenide are continuously continuous at a rate of 0.6 mmol/h and 0.6 mmol/h, respectively. Inject 20 min into the reaction system. Subsequently, the cadmium oleate precursor and the trioctylphosphine sulfide precursor were continuously injected into the reaction system at a rate of 0.4 mmol/h and 6 mmol/h, respectively, for 1 hour. After the reaction was completed, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a blue quantum dot (CdZnS/CdZnSe/) having a quantum well level structure (specific structure 4). CdZnS).

Example 22: Preparation of green quantum dots with specific structure 4

0.4 mmol of Selenium powder was dissolved in 2 mL of Trioctylphosphine to obtain a trioctylphosphine selenide precursor.

0.8 mmol of cadmium oxide (CdO), 1.2 mL of oleic acid (Oleic acid) and 4.8 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask, and heated under reflux in a nitrogen atmosphere at 250 ° C for 120 min to obtain a transparent oleic acid. Cadmium precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form Cd _x Zn _{1 -x} S. After 10 minutes of reaction, the oil was oiled. The cadmium acid precursor and the trioctylphosphine selenide precursor were continuously injected into the reaction system at a rate of 0.6 mmol/h and 0.6 mmol/h, respectively, for 40 min. Subsequently, the cadmium oleate precursor and the trioctylphosphine sulfide precursor were continuously injected into the reaction system at a rate of 0.4 mmol/h and 6 mmol/h, respectively, for 1 hour. After the reaction was completed, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green quantum dot (CdZnS/CdZnSe/CdZnS having a quantum well level structure (specific structure 4). ).

Example 23: Preparation of red quantum dots with specific structure 4

1.5 mmol of Selenium powder, 1.75 mmol of sulfur powder (Sulfur powder) was dissolved in 3 mL of Trioctylphosphine to obtain trioctylphosphine selenide-trioctylphosphine sulfide precursor 1.

1 mmol of Selenium powder was placed in 2 mL of Trioctylphosphine to obtain a trioctylphosphine selenide precursor.

0.2 mmol of Selenium powder and 0.8 mmol of sulfur powder (Sulfur powder) were dissolved in 2 mL of Trioctylphosphine to obtain trioctylphosphine selenide-trioctylphosphine sulfide precursor 2.

3 mmol of cadmium oxide (CdO), 3 mL of oleic acid (Oleic acid) and 6 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask, and heated under reflux in a nitrogen atmosphere at 250 ° C for 120 min to obtain a transparent cadmium oleate precursor. .

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine selenide-trioctylphosphine sulfide precursor 1 was injected into the reaction system to form Cd _x Zn _1‐x. Se, after reacting for 10 min, 2 mL of a trioctylphosphine selenide precursor and 3 mL of a cadmium oleate precursor were added dropwise to the reaction system at a rate of 4 mL/h and 6 mL/h, respectively. At 30 min, 2 mL of trioctylphosphine selenide-

trioctylphosphine sulfide precursor

2 and 3 mL of cadmium oleate precursor were added dropwise to the reaction system at a rate of 2 mL/h and 3 mL/h, respectively. After the reaction is completed, after the reaction solution is cooled to room temperature, the product is repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red quantum dot of specific structure 4 (Cd _x Zn _{1 -x} Se/CdZnSe/Cd _z Zn _1‐z SeS).

Example 24: Preparation of blue quantum dots with specific structure 5

1 mmol of sulfur powder (Sulfur powder) was dissolved in 3 mL of octadecene (1 - Octadecene) to obtain a thiooctadecene precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form Cd _x Zn _{1 -x} S. After 10 minutes of reaction, 3 mL was obtained. The trioctylphosphine sulfide precursor was continuously injected into the reaction system at a rate of 3 mL/h for 1 h. When the trioctylphosphine sulfide precursor was injected for 20 min, 2 mL of the cadmium oleate precursor was injected into the reaction system at 6 mL/h. When the trioctylphosphine sulfide precursor was injected for 40 min, 4 mL of a cadmium oleate precursor was injected into the reaction system at 12 mL/h. After the reaction was completed, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a blue quantum dot (CdZnS/ZnS/) having a quantum well level structure (specific structure 5). CdZnS).

Example 25: Preparation of green quantum dots with specific structure 5

0.4 mmol of Selenium powder and 4 mmol of sulfur powder were dissolved in 4 mL of Trioctylphosphine to obtain trioctylphosphine selenide-sulfide Octylphosphine precursor 1.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine trisulfide sulfide trioctylphosphine precursor was rapidly injected into the reaction system to form Cd _x Zn _1‐x. Se _y S _1‐y , after reacting for 10 min, 3 mL of the trioctylphosphine sulfide precursor was continuously injected at a rate of 3 mL/h for 1 h into the reaction system. When the trioctylphosphine sulfide precursor was injected for 20 min, 2 mL of oleic acid was added. The cadmium precursor was injected into the reaction system at 6 mL/h. When the trioctylphosphine sulfide precursor was injected for 40 min, 4 mL of the cadmium oleate precursor was injected into the reaction system at 12 mL/h. After the reaction is completed, after the reaction solution is cooled to room temperature, the product is repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green quantum dot (CdZnSeS/ZnS/CdZnS having a quantum well level structure (specific structure 5). ).

Example 26: Preparation of red quantum dots with specific structure 5

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to form Cd _x Zn _{1 -x} Se. After 10 minutes of reaction, The trioctylphosphine sulfide precursor was continuously injected into the reaction system at a rate of 6 mmol/h for 1 h. When S-TOP was injected for 20 min, 0.2 mmol of cadmium oleate precursor was injected into the reaction system at 0.6 mmol/h. When S-TOP was injected for 40 min, 0.4 mmol of cadmium oleate precursor was injected into the reaction system at 1.2 mmol/h. After the reaction is completed, after the reaction solution is cooled to room temperature, the product is repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red quantum dot (CdZnSe/ZnS/CdZnS having a quantum well level structure (specific structure 5). ).

Example 27: Preparation of Blue Quantum Dots with Specific Structure 6

Preparation of cadmium oleate and zinc oleate precursor: 1 mmol of cadmium oxide (CdO), 9 mmol of zinc acetate [Zn(acet) 2], 8 mL of oleic acid (Oleic acid), and 15 mL of octadecene (1‐Octadecene) were placed. In a 100 mL three-necked flask, vacuum degassing was carried out at 80 ° C for 60 min. It is then switched to a nitrogen atmosphere and stored at this temperature for use.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to form Cd _x Zn _{1 -x} S. After 10 minutes of reaction, the sulfide was vulcanized. The trioctylphosphine precursor and the cadmium oleate precursor were added dropwise to the reaction system at a rate of 6 mmol/h and 0.6 mmol/h, respectively. After 30 min, the temperature of the reaction system was lowered to 280 ° C, and the remaining trioctylphosphine sulfide precursor and cadmium oleate precursor were added dropwise to the reaction system at a rate of 6 mmol/h and 0.6 mmol/h, respectively. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a blue quantum dot (Cd _x Zn _{1 - x} S) having a specific structure of 6.

Example 28: Preparation of Green Quantum Dots with Specific Structure 6

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine trisulfide sulfide trioctylphosphine precursor was rapidly injected into the reaction system to form Cd _x Zn _1‐x. SeyS _1‐y , after reacting for 10 min, the temperature of the reaction system was lowered to 280 ° C, and the trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 4 mL/h. After the reaction is completed, after the reaction solution is cooled to room temperature, the product is repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green quantum dot having a specific structure of 6 (Cd _x Zn _{1 -x} Se _y S _1‐y /ZnS).

Example 29: Preparation of red quantum dots with specific structure 6

0.2 mmol of Selenium powder, 0.6 mmol of sulfur powder (Sulfur powder) Dissolved in 2 mL of Trioctylphosphine to obtain a trioctylphosphine selenide-trioctylphosphine sulfide precursor.

The cadmium oleate and zinc oleate precursors were heated to 310 ° C under a nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to form Cd _x Zn _{1 -x} Se. After 10 minutes of reaction, The temperature of the reaction system was lowered to 280 ° C, and a trioctylphosphine selenide-trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 4 mL/h. After completion of the reaction, after the reaction liquid was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red quantum dot (Cd _x Zn _{1 -x} Se/ZnSeS) having a specific structure of 6.

Example 30: Preparation of green quantum dots with specific structure 7

Preparation of cadmium oleate first precursor: 1 mmol of cadmium oxide (CdO), 1 mL of oleic acid (Oleic acid) and 5 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask and vacuum degassed at 80 ° C for 60 mins. . It is then switched to a nitrogen atmosphere and stored at this temperature for use.

Preparation of cadmium oleate second precursor: 0.6 mmol of cadmium oxide (CdO), 0.6 mL of oleic acid (Oleic acid) and 5.4 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask at 250 ° C under nitrogen atmosphere. Heating under reflux for 120 mins gave a transparent second precursor of cadmium oleate.

Preparation of zinc oleate precursor: 9 mmol of zinc acetate [Zn(acet) ₂ ], 7 mL of oleic acid (Oleic acid), and 10 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask and vacuumed at 80 ° C. Degas for 60mins. Then, it was switched to a nitrogen atmosphere, and it was heated and refluxed at 250 ° C under a nitrogen atmosphere to be ready for use.

The first precursor of cadmium oleate was heated to 310 ° C under a nitrogen atmosphere, and the thiooctadecene precursor was rapidly injected into the reaction system to rapidly form CdS. After 10 mins of reaction, the zinc oleate precursor was introduced. The whole body was injected into the reaction system, and then 3 mL of the trioctylphosphine sulfide precursor and 6 mL of the cadmium oleate precursor were simultaneously injected into the reaction system at a rate of 3 mL/h and 10 mL/h, respectively.

After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a blue quantum dot having a quantum well level structure.

Example 31: Preparation of green quantum dots with specific structure 7

Preparation of cadmium oleate precursor: 0.4 mmol of cadmium oxide (CdO), 1 mL of oleic acid (Oleic acid) and 5 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask and vacuum degassed at 80 ° C for 60 mins. It was then heated to reflux at 250 ° C under a nitrogen atmosphere and stored at this temperature for use.

0.4 mmol of Selenium powder was dissolved in 4 mL of Trioctylphosphine to obtain trioctylphosphine selenide.

Preparation of zinc oleate precursor: 8 mmol of zinc acetate [Zn(acet) ₂ ], 9 mL of oleic acid (Oleic acid) and 15 mL of octadecene (1 -Octadecene) were placed in a 100 mL three-necked flask and vacuum-desorbed at 80 ° C. Gas 60mins. The mixture was heated under reflux at 250 ° C for 120 min in a nitrogen atmosphere to obtain a transparent zinc oleate precursor.

2 mmol of sulfur powder (Sulfur powder) and 1.6 mmol of selenium powder (Selenium powder) were dissolved in 2 mL of Trioctylphosphine to obtain a trioctylphosphine selenide-trioctylphosphine sulfide precursor.

The cadmium oleate precursor was heated to 310 ° C under nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to rapidly form CdSe. After 5 mins, all the zinc oleate precursors were injected into the reaction. In the system, 2 mL of a trioctylphosphine selenide-trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 2 mL/h until the precursor was injected. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a green fluorescent quantum dot having a quantum well level structure.

Example 32: Preparation of red quantum dots with specific structure 7

Preparation of cadmium oleate precursor: 0.8mmol cadmium oxide (CdO), 4mL oleic acid (Oleic acid) And 10 mL of octadecene (1 - Octadecene) was placed in a 100 mL three-necked flask, and vacuum degassed at 80 ° C for 60 mins. It was then heated to reflux at 250 ° C under a nitrogen atmosphere and stored at this temperature for use.

Zinc oleate precursor preparation: 12mmol zinc acetate [Zn(acet) ₂ ], 10mL oleic acid (Oleic acid) and 10mL octadecene (1‐Octadecene) were placed in a 100mL three-necked flask and vacuum degassed at 80 ° C 60mins.

0.8 mmol of Selenium powder was placed in 4 mL of Trioctylphosphine to obtain a trioctylphosphine selenide precursor.

1 mmol of Selenium powder, 0.6 mmol of sulfur powder (Sulfur powder) was dissolved in 2 mL of Trioctylphosphine to obtain a trioctylphosphine selenide-trioctylphosphine sulfide precursor.

The cadmium oleate precursor was heated to 310 ° C under nitrogen atmosphere, and the trioctylphosphine precursor was quickly injected into the reaction system to rapidly form CdSe. After 10 mins of reaction, the zinc oleate precursor was injected into the reaction. In the system, 2 mL of a trioctylphosphine selenide-trioctylphosphine sulfide precursor was added dropwise to the reaction system at a rate of 4 mL/h. After completion of the reaction, after the reaction solution was cooled to room temperature, the product was repeatedly dissolved and precipitated with toluene and anhydrous methanol, and purified by centrifugation to obtain a red fluorescent quantum dot having a quantum well level structure.

Embodiment 33: The top-mounted QLED device in this embodiment, as shown in FIG. 16, includes, in order from bottom to top, a glass substrate 101, an Al anode 102, a PEDOT: PSS hole injection layer 103, and a poly-TPD space. The hole transport layer 104, the quantum dot light emitting layer 105, the ZnO electron transport layer 106, and the ITO cathode 107.

The preparation steps of the above-mentioned top-mounted QLED device are as follows:

A 100 nm Al anode 102 was prepared by vacuum evaporation on a glass substrate 101, and then a 30 nm PEDOT:PSS hole injection layer 103 and a 30 nm poly-TPD hole transport layer 104 were sequentially prepared, followed by poly-TPD hole transport. A layer of quantum dot luminescent layer 105 is prepared on layer 104 to a thickness of 20 nm, and then a 40 nm ZnO electron transport layer 106 is prepared on the quantum dot luminescent layer 105. Finally, a 120 nm ITO cathode was prepared as a top electrode by sputtering. The quantum dot material of the quantum dot light-emitting layer 105 is a quantum dot material as described in the examples.

Embodiment 34: The bottom-mounted QLED device in this embodiment, as shown in FIG. 17, includes, in order from bottom to top, a substrate 201, an ITO anode 202, a PEDOT: PSS hole injection layer 203, and a poly-TPD space. The hole transport layer 204, the quantum dot light emitting layer 205, the ZnO electron transport layer 206, and the Al cathode 207.

The preparation steps of the above-mentioned bottom-mounted QLED device are as follows:

After sequentially preparing an ITO anode 202, a 30 nm PEDOT:PSS hole injection layer 203, and a 30 nm poly-TPD hole transport layer 204 on the substrate 201, a quantum dot light-emitting layer 205 is prepared on the poly-TPD hole transport layer 204. The thickness was 20 nm, and then a 40 nm ZnO electron transport layer 206 and a 100 nm Al cathode 207 were prepared on the quantum dot light-emitting layer 205. The quantum dot material of the quantum dot luminescent layer 205 is a quantum dot material as described in the examples.

Embodiment 35: The bottom-mounted QLED device in this embodiment, as shown in FIG. 18, includes a substrate 301, an ITO anode 302, a PEDOT: PSS hole injection layer 303, and a Poly (9-) from bottom to top. A vinylcarbazole (PVK) hole transport layer 304, a quantum dot light-emitting layer 305, a ZnO electron transport layer 306, and an Al cathode 307.

After sequentially preparing an ITO anode 302, a 30 nm PEDOT:PSS hole injection layer 303, and a 30 nm PVK hole transport layer 304 on the substrate 301, a quantum dot light-emitting layer 305 is prepared on the PVK hole transport layer 304 to a thickness of 20 nm. Then, a 40 nm ZnO electron transport layer 306 and a 100 nm Al cathode 307 were prepared on the quantum dot light-emitting layer 305. The quantum dot material of the quantum dot luminescent layer 305 is a quantum dot material as described in the examples.

Embodiment 36: The bottom-mounted QLED device of the present embodiment, as shown in FIG. 19, includes, in order from bottom to top, a substrate 401, an ITO anode 402, a PEDOT: PSS hole injection layer 403, and a poly-TPD space. The hole transport layer 404, the quantum dot light-emitting layer 405, the TPBi electron transport layer 406, and the Al cathode 407.

An ITO anode 402, a 30 nm PEDOT:PSS hole injection layer was sequentially prepared on the substrate 401. After the 403 and 30 nm poly-TPD hole transport layer 404, a quantum dot light-emitting layer 405 is prepared on the poly-TPD hole transport layer 404 to a thickness of 20 nm, and then subjected to a vacuum evaporation method on the quantum dot light-emitting layer 405. A 30 nm TPBi electron transport layer 406 and a 100 nm Al cathode 407 were prepared. The quantum dot material of the quantum dot luminescent layer 405 is a quantum dot material as described in the examples.

Embodiment 37: The inverted top emission QLED device in this embodiment, as shown in FIG. 20, includes a glass substrate 501, an Al cathode 502, a ZnO electron transport layer 503, a quantum dot light emitting layer 504, and an NPB, as shown in FIG. The hole transport layer 505, the MoO ₃ hole injection layer 506, and the ITO anode 507.

The preparation steps of the above-mentioned inverted top emission QLED device are as follows:

A 100 nm Al cathode 502 was prepared by vacuum evaporation on a glass substrate 501, and then a 40 nm ZnO electron transport layer 503 was prepared, and a quantum dot light-emitting layer 504 was prepared on the ZnO electron transport layer 503 to a thickness of 20 nm. Then, a 30 nm NPB hole transport layer 505 and a 5 nm MoO ₃ hole injection layer 506 were prepared by vacuum evaporation on the quantum dot light-emitting layer 504, and finally a 120 nm ITO anode was prepared by sputtering. The quantum dot material of the quantum dot luminescent layer 505 is a quantum dot material as described in the examples.

Embodiment 38: The reverse-bottom-emitting QLED device in this embodiment, as shown in FIG. 21, includes a substrate 601, an ITO cathode 602, a ZnO electron transport layer 603, a quantum dot light-emitting layer 604, and an NPB, as shown in FIG. The hole transport layer 605, the MoO ₃ hole injection layer 606, and the Al anode 607.

The preparation steps of the above-mentioned reverse bottom emission QLED device are as follows:

An ITO cathode 602 and a 40 nm ZnO electron transport layer 603 are sequentially prepared on the substrate 601, and a quantum dot light-emitting layer 604 is prepared on the ZnO electron transport layer 603 to a thickness of 20 nm, followed by vacuum evaporation on the quantum dot light-emitting layer 604. A 30 nm NPB hole transport layer 605, a ₅ nm MoO ₃ hole injection layer 606 and a 100 nm Al anode 607 were prepared by a plating method. The quantum dot material of the quantum dot luminescent layer 605 is a quantum dot material as described in the examples.

The present invention also provides a method for preparing a top-mounted QLED device as in the first embodiment described above. As shown in FIG. 22, the preparation method includes the following steps:

S100, providing a substrate, forming a reflective anode on the substrate;

S200, sequentially depositing a hole transport layer, a quantum dot light emitting layer, and an electron transport layer on the reflective anode;

S300, depositing a transparent cathode on the electron transport layer to produce a top-mounted emission QLED device.

Further, after the step S100 and before the step S200, the method further includes the following steps:

S201: performing a cleaning process on the substrate having the reflective anode;

S202. Perform oxygen plasma treatment or ultraviolet ozone treatment on the cleaned substrate with the reflective anode.

That is, the present invention forms a reflective electrode on a substrate such as glass to reflect an anode, such as Al/ITO, and then cleans the substrate having a reflective electrode of Al/ITO, specifically, the substrate is sequentially washed with a liquid, Ultrapure water, acetone and isopropyl alcohol were washed and continuously sonicated for 15 minutes, then dried in an oven at 80 ° C for use, and then the substrate after the cleaning treatment was subjected to oxygen plasma treatment or ultraviolet ozone treatment for 30 minutes to further Clean the surface of the electrode and increase its work function; then deposit a hole injection layer, a hole transport layer, a quantum dot light-emitting layer and an electron transport layer on the reflective cathode by solution processing or vacuum evaporation, the solution processing method includes Spin coating, printing, spraying, etc., the vacuum evaporation method includes vacuum thermal evaporation, sputtering, etc., and can be selected according to actual needs.

The present invention also provides a method for fabricating a bottom-mounted QLED device as in the third embodiment described above. As shown in FIG. 23, the preparation method includes the following steps:

S110, providing a substrate, forming a transparent anode on the substrate;

S210, sequentially depositing a hole transport layer, a quantum dot light emitting layer, and an electron transport layer on the transparent anode;

S310, vapor depositing a reflective cathode on the electron transport layer to obtain a bottom-mounted QLED device.

Further, after the step S110 and before the step S210, the method further includes the following steps:

S211, performing a cleaning process on the substrate having a transparent anode;

S212. Perform oxygen plasma treatment or ultraviolet ozone treatment on the cleaned substrate with a transparent anode.

That is, the present invention forms a transparent anode, such as a patterned ITO electrode, on a substrate such as glass, and then cleans the substrate (ie, ITO substrate) having a transparent anode, specifically, the ITO substrate is washed sequentially. Washed with liquid, ultrapure water, acetone and isopropanol and continuously sonicated for 15 minutes, then dried in an oven at 80 ° C for use, then subjected to oxygen plasma treatment or UV ozone treatment for 30 minutes after the cleaning of the ITO substrate. To further clean the ITO surface and improve the work function of the ITO; thereafter, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, and an electron transport layer are sequentially deposited on the ITO substrate by a solution processing method or a vacuum evaporation method. The solution processing method includes spin coating, printing, spraying, etc., and the vacuum evaporation method includes vacuum thermal evaporation, sputtering, etc., and can be selected according to actual needs.

The present invention also provides a method for preparing an inverted top emission QLED device according to the fifth embodiment described above. As shown in FIG. 24, the preparation method includes the following steps:

S120, providing a substrate, forming a reflective cathode on the substrate;

S220, sequentially depositing an electron transport layer, a quantum dot light emitting layer, and a hole transport layer on the reflective cathode;

S320, depositing a transparent anode on the hole transport layer to obtain a reverse top emitting QLED device.

Further, after the step S120 and before the step S220, the method further includes the following steps:

S221, performing a cleaning process on the substrate having the reflective cathode;

S222, performing oxygen plasma treatment or ultraviolet ozone treatment on the cleaned substrate with the reflective cathode.

That is, the present invention forms a reflective cathode, such as a reflective electrode of Al/ITO, on a substrate such as glass, and then cleans the substrate having the reflective electrode of Al/ITO, specifically, the substrate is sequentially washed with a liquid, Ultrapure water, acetone and isopropyl alcohol were washed and continuously sonicated for 15 minutes, then dried in an oven at 80 ° C for use, and then subjected to oxygen plasma treatment on the cleaned substrate. Or UV ozone treatment for 30 minutes to further clean the click surface and improve its work function; then deposit the electron transport layer, quantum dot light-emitting layer, hole transport layer and empty on the ITO substrate by solution processing or vacuum evaporation. The solution processing method includes spin coating, printing, spraying, etc., and the vacuum evaporation method includes vacuum thermal evaporation, sputtering, etc., and may be selected according to actual needs.

The present invention also provides a method for preparing a reverse-bottom-emitting QLED device according to the seventh embodiment described above. As shown in FIG. 25, the preparation method includes the following steps:

S130, providing a substrate, forming a transparent cathode on the substrate;

S230, sequentially depositing an electron transport layer, a quantum dot light emitting layer, and a hole transport layer on the transparent cathode;

S330, depositing a reflective anode on the hole transport layer to obtain a reverse bottom emission QLED device.

Further, after the step S130 and before step S230, the method further includes the steps of:

S231, performing a cleaning process on the substrate having a transparent cathode;

S232. Perform oxygen plasma treatment or ultraviolet ozone treatment on the cleaned substrate with a transparent cathode.

That is, the present invention forms a transparent cathode, such as a patterned ITO electrode, on a substrate such as glass, and then cleans the substrate (ie, ITO substrate) having a transparent cathode, specifically, the ITO substrate is washed sequentially. Washed with liquid, ultrapure water, acetone and isopropanol and continuously sonicated for 15 minutes, then dried in an oven at 80 ° C for use, then subjected to oxygen plasma treatment or UV ozone treatment for 30 minutes after the cleaning of the ITO substrate. To further clean the ITO surface and improve the work function of the ITO; thereafter, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer, and a hole injection layer are sequentially deposited on the ITO substrate by a solution processing method or a vacuum evaporation method. The solution processing method includes spin coating, printing, spraying, etc., and the vacuum evaporation method includes vacuum thermal evaporation, sputtering, etc., and can be selected according to actual needs.

The preparation method of the QLED device provided by the present invention and the specific device performance will be further described below by using the embodiments.

The top-mounted emission QLED device provided by the first application embodiment is prepared by:

1. Cleaning of the glass substrate of the reflective electrode (ie, anode) containing Al/ITO: washing with washing liquid, ultrapure water, acetone and isopropyl alcohol, and continuously sonicating for 15 minutes, and then drying in an oven at 80 ° C, Treated under UVO for 30 minutes to clean the ITO surface and enhance the work function of the ITO electrode;

2. Preparation of hole injection layer and hole transport layer: PEDOT:PSS was spin-coated at 5,000 rpm on the cleaned glass substrate in air, and the spin coating time was 40 s. After the spin coating was completed, the air was applied. Annealing at 150 ° C for 15 min, drying the non-volatile liquid, then transferring it into a glove box (O ₂ <1 ppm, H ₂ O <1 ppm), and spinning the TFB chlorine on the PEDOT:PSS layer at 3000 rpm. Benzene solution (concentration 8mg/ml), spin coating time 30s. After the spin coating is completed, annealing in a glove box at 150 ° C for 30 minutes to remove the remaining solvent to form a TFB layer;

3. Preparation of quantum dot luminescent layer: After annealing, the quantum dot solution is spin-coated, wherein the quantum dot is CdSe/CdS core-shell structure, dispersed in n-octane, the concentration is about 15 mg/ml, and the rotation speed is 2000 rpm. Spin coating time 40s;

4. Preparation of electron transport layer: After the spin coating of the quantum dot solution is completed, a layer of ZnO ethanol solution is spin-coated, wherein the rotation speed is 3000 rpm, the spin coating time is 30 s; the concentration of ethanol is 30 mg/ml;

5. Preparation of transparent cathode: The spin-coated device was placed in a vacuum evaporation chamber, 15 nm thick aluminum was vapor-deposited as a cathode, and 200 nm thick MoOx was deposited as a protective layer on Al to obtain the quantum of the first application example. Point light emitting device.

In a second application embodiment, as shown in FIG. 26, FIG. 27 and FIG. 28, the prepared QLED device is a red light emitting device with an emission wavelength of 630 nm, and the turn-on voltage is only about 2 V, and the brightness can reach about 15500 cd at a driving voltage of 5 V. /m ² , the external quantum efficiency is about 6%, and a highly efficient and stable QLED device is obtained, and the preparation method is as follows:

1. Cleaning of glass substrate containing ITO transparent electrode (ie anode): washing with washing liquid, ultrapure water, acetone and isopropanol and continuous sonication for 15 minutes, then drying in an oven at 80 ° C under UVO Treated for 30 minutes to clean the ITO surface and enhance the work function of the ITO electrode;

5. Preparation of Cathode: The spin-coated device was placed in a vacuum evaporation chamber, and 100 nm thick aluminum was vapor-deposited as a cathode to obtain a quantum dot light-emitting device of the second application example.

In a third application embodiment, as shown in FIG. 29, FIG. 30 and FIG. 31, the prepared QLED device is a green light emitting device with an emission wavelength of 520 nm, and the turn-on voltage is only about 2.5 V, and the brightness can reach about 5 V under the driving voltage. 9000cd / m ^2, the external quantum efficiency of more than 10%, significantly improved the efficiency of the device, which is prepared as follows:

2. Preparation of hole injection layer and hole transport layer: PEDOT:PSS was spin-coated at 5,000 rpm on the cleaned glass substrate in air, and the spin coating time was 40 s. After the spin coating was completed, the air was applied. Annealing at 150 ° C for 15 min, drying the non-volatile liquid, then transferring it into a glove box (O ₂ <1 ppm, H ₂ O <1 ppm), and spinning the TFB chlorine on the PEDOT:PSS layer at 3000 rpm. Benzene solution (concentration of 8mg / ml), spin coating time of 30s, after spin coating is completed, annealing in a glove box at 150 ° C for 30 minutes to remove the remaining solvent to form a TFB layer;

3. Preparation of quantum dot luminescent layer: After annealing, spin-coating quantum dot solution, the quantum dots therein It is a CdSe/CdS core-shell structure dispersed in n-octane at a concentration of about 15 mg/ml, a rotation speed of 2000 rpm, and a spin coating time of 40 s;

5. Preparation of Cathode: The spin-coated device was placed in a vacuum evaporation chamber, and 100 nm thick aluminum was vapor-deposited as a cathode to obtain a quantum dot light-emitting device of the third application example.

In a fourth application embodiment, as shown in FIG. 32, FIG. 33 and FIG. 34, the prepared QLED device is a blue light device with an emission wavelength of 460 nm, and the maximum external quantum efficiency thereof has exceeded 13%, the turn-on voltage is about 5 V, and the brightness is 5 V. The driving voltage is 3500 cd/m ² , and the device efficiency is obviously improved. The preparation method is as follows:

2. Preparation of hole injection layer and hole transport layer: PEDOT:PSS was spin-coated at 5,000 rpm on the cleaned glass substrate in air, and the spin coating time was 40 s. After the spin coating was completed, the air was applied. Annealing at 150 ° C for 15 min, drying the non-volatile liquid, then transferring it into a glove box (O ₂ <1 ppm, H ₂ O <1 ppm), and spinning PVK chlorine at 3000 rpm on the PEDOT:PSS layer. Benzene solution (concentration of 8mg/ml), spin coating time of 30s, after spin coating is completed, annealing in a glove box at 150 ° C for 30 minutes to remove the remaining solvent to form a PVK layer;

5. Preparation of Cathode: The spin-coated device was placed in a vacuum evaporation chamber, and 100 nm thick aluminum was vapor-deposited as a cathode to obtain a quantum dot light-emitting device of the fourth application example.

The reverse top emitting QLED device provided by the fifth application embodiment is prepared by:

1. Cleaning of the glass substrate of the reflective electrode (ie cathode) containing Al/ITO: washing with washing liquid, ultrapure water, acetone and isopropyl alcohol and continuously sonicating for 15 minutes, and then drying in an oven at 80 ° C, Treated under UVO for 30 minutes to clean the ITO surface and enhance the work function of the ITO electrode;

2. Preparation of electron transport layer: spin-coating a layer of ZnO ethanol solution on ITO, wherein the rotation speed is 3000 rpm, the spin coating time is 30 s; the concentration of ethanol is 30 mg/ml;

4. Preparation of hole transport layer and hole injection layer: After the spin coating of the quantum dot solution is completed, the spin-coated device is placed in a vacuum evaporation chamber, and 40 nm CBP is vapor-deposited as a hole transport layer, and 10 nm MoOx is used as an empty layer. Hole injection layer;

5. Preparation of Transparent Anode: A quantum dot light-emitting device of a fifth application example was obtained by vapor-depositing 15 nm thick aluminum as a cathode and vapor-depositing 200 nm thick MoOx as a protective layer on Al.

The anti-bottom-emitting QLED device provided by the sixth application embodiment is prepared by:

1. Cleaning of glass substrate containing ITO transparent electrode (ie cathode): washing with washing liquid, ultrapure water, acetone and isopropanol and continuous sonication for 15 minutes, then drying in an oven at 80 ° C under UVO Treated for 30 minutes to clean the ITO surface and enhance the work function of the ITO electrode;

5. Preparation of anode: The spin-coated device was placed in a vacuum evaporation chamber, and 100 nm thick aluminum was vapor-deposited as an anode to obtain a quantum dot light-emitting device of the sixth application example.

In summary, in the QLED device and the preparation method thereof, the QLED device includes a substrate, a reflective anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a transparent cathode which are sequentially stacked. The quantum dot luminescent layer is prepared by using a quantum dot material having a quantum well level structure, and the quantum dot material includes at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is A gradual alloy composition with a change in energy level width in the radial direction or a uniform composition structure with uniform energy levels in the radial direction can achieve excellent performances such as high-efficiency charge injection, high luminance, low driving power, and high device efficiency. Efficient QLED device.

It is to be understood that those skilled in the art can make equivalent substitutions or changes to the inventions and the inventions of the present invention, and all such changes or substitutions fall within the scope of the appended claims.

Claims

A QLED device comprising a substrate, a reflective anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a transparent cathode, which are sequentially stacked, wherein the quantum dot light emitting layer has a quantum well level The quantum dot material of the structure is prepared, and the quantum dot material comprises at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy group whose energy level width changes in a radial direction A uniform composition of structures having uniform energy levels in the substructure or radial direction.
The QLED device according to claim 1, further comprising a hole injecting layer disposed between said reflective anode and said hole transporting layer.
The upright emitting QLED device according to claim 1 or 2, wherein the reflective anode is an aluminum electrode or a silver electrode, and the reflective anode has a thickness of 30-800 nm.
The upright emitting QLED device according to claim 1 or 2, wherein the transparent cathode is ITO or a thin metal electrode, the thickness of the ITO is 20-300 nm, and the thickness of the thin metal electrode is 5‐50 nm.
A QLED device comprising a substrate stacked in sequence, a transparent anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a reflective cathode, wherein the quantum dot light emitting layer has a quantum well level The quantum dot material of the structure is prepared, and the quantum dot material comprises at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy group whose energy level width changes in a radial direction A uniform composition of structures having uniform energy levels in the substructure or radial direction.
The QLED device according to claim 5, further comprising a hole injecting layer disposed between said transparent anode and said hole transporting layer.
The QLED device according to claim 5 or 6, wherein the transparent yang Extremely patterned ITO.
The QLED device according to claim 5 or 6, wherein the reflective cathode is an aluminum electrode or a silver electrode, and the reflective cathode has a thickness of 30 to 800 nm.
A QLED device comprising a substrate, a reflective cathode, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer and a transparent anode, which are sequentially stacked, wherein the quantum dot light-emitting layer has a quantum well level The quantum dot material of the structure is prepared, and the quantum dot material comprises at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy group whose energy level width changes in a radial direction A uniform composition of structures having uniform energy levels in the substructure or radial direction.
The QLED device according to claim 9, further comprising a hole injecting layer provided between said hole transporting layer and said transparent anode.
The QLED device according to claim 9 or 10, wherein the reflective cathode is an aluminum electrode or a silver electrode, and the reflective cathode has a thickness of 30 to 800 nm.
The QLED device according to claim 9 or 10, wherein the transparent anode is ITO or a thin metal electrode, the thickness of the ITO is 20-300 nm, and the thickness of the thin metal electrode is 5-50 nm. .
A QLED device comprising a substrate, a transparent cathode, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer and a reflective anode, which are sequentially stacked, wherein the quantum dot light-emitting layer has a quantum well level The quantum dot material of the structure is prepared, and the quantum dot material comprises at least one quantum dot structural unit sequentially arranged in a radial direction, and the quantum dot structural unit is a graded alloy group whose energy level width changes in a radial direction A uniform composition of structures having uniform energy levels in the substructure or radial direction.
The QLED device according to claim 13, further comprising a hole injection layer disposed between said hole transport layer and said reflective anode.
A QLED device according to claim 13 or 14, wherein the transparent cathode is patterned ITO.
The QLED device according to claim 13 or 14, wherein the reflective anode is an aluminum electrode or a silver electrode, and the reflective anode has a thickness of 30 to 800 nm.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot structural unit is a graded alloy in which the width of the outer level is wider in the radial direction. The compositional structure, and the energy levels of the quantum dot structural units adjacent in the radial direction are continuous.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein said quantum dot material comprises at least three quantum dot structural units arranged in order in the radial direction Wherein, among the at least three quantum dot units, the quantum dot structural unit at the center and the surface are both graded alloy composition structures having a wider outer level width in the radial direction, and are adjacent in the radial direction The energy level of the quantum dot structural unit of the graded alloy component structure is continuous; a quantum dot structural unit between the central and surface quantum dot structural units is a uniform composition structure.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein said quantum dot material comprises two types of quantum dot structural units, wherein one type of quantum dot The structural unit is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the other type of quantum dot structural unit is a graded alloy composition having a narrower outer diameter level in the radial direction. The two types of quantum dot structural units are alternately arranged in the radial direction, and the energy levels of adjacent quantum dot structural units in the radial direction are continuous.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot structural unit is a graded alloy in which the width of the outer level is wider in the radial direction. The composition structure, and the energy levels of adjacent quantum dot structural units are discontinuous.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot structural unit is a graded alloy in which the width of the outer level is narrower in the radial direction. The composition structure, and the energy levels of adjacent quantum dot structural units are discontinuous.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein said quantum dot material comprises two quantum dot structural units, wherein one quantum dot structural unit is a diameter The gradual alloy composition structure in which the width of the outer level is wider in the direction, the other quantum dot structural unit is a uniform composition structure, and the interior of the quantum dot material includes one or more quantum structures of the gradual alloy composition. Point structure unit, and the energy level of the quantum dot structure unit of the graded alloy composition structure adjacent in the radial direction is continuous; the outer portion of the quantum dot material includes one or more quantum dots of a uniform composition structure Structural units.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein said quantum dot material comprises two quantum dot structural units, wherein one quantum dot structural unit is uniform Component structure, another quantum dot structural unit is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the interior of the quantum dot material includes one or more quantum dots of a uniform composition structure a structural unit, the outer portion of the quantum dot material comprising one or more quantum dot structural units of a graded alloy composition structure, and the energy level of the quantum dot structural unit of the graded alloy composition structure adjacent in the radial direction is continuously.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot structural unit is a graded alloy component structure or uniform comprising a group II and group VI element Alloy component structure.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot structural unit comprises a 2-20 layer monoatomic layer, or the quantum dot structural unit Contains 1 - 10 layers of cell layers.
QLED according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14 The device is characterized in that the quantum dot material has an emission peak wavelength ranging from 400 nm to 700 nm.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot material has a half peak width of 12 nm to 80 nm.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the quantum dot light-emitting layer has a thickness of 10 to 100 nm.
The QLED device according to claim 2 or 6 or 10 or 14, wherein the material of the hole injection layer is at least one of PEDOT:PSS, MoO 3 , VO 2 or WO 3 .
The QLED device according to claim 29, wherein the hole injecting layer has a thickness of 10 to 150 nm.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the material of the hole transport layer is TFB, poly-TPD, PVK, NiO, MoO 3 , At least one of NPB and CBP.
The upright-emitting QLED device according to claim 31, wherein the hole transport layer has a thickness of 10 - 150 nm.
The QLED device according to claim 1 or 2 or 5 or 6 or 9 or 10 or 13 or 14, wherein the material of the electron transport layer is LiF, CsF, Cs 2 CO 3 , ZnO, Alq 3 At least one of them.
The QLED device according to claim 33, wherein said electron transport layer has a thickness of 10 - 150 nm.
A method of fabricating a QLED device according to claim 1, comprising the steps of:

A, providing a substrate, forming a reflective anode on the substrate;

B. sequentially depositing a hole transport layer, a quantum dot light emitting layer, and an electron transport layer on the reflective anode;

C. Depositing a transparent cathode on the electron transport layer to produce a top-mounted QLED device.
The method of producing a QLED device according to claim 35, wherein the hole transporting layer, the quantum dot light emitting layer, and the electron transporting layer are deposited by a solution processing method or a vacuum evaporation method.
A method of fabricating a QLED device according to claim 5, comprising the steps of:

A, providing a substrate, forming a transparent anode on the substrate;

B. sequentially depositing a hole transport layer, a quantum dot light emitting layer, and an electron transport layer on the transparent anode;

C. Depositing a reflective cathode on the electron transport layer to produce a positive-bottom-emitting QLED device.
The method of fabricating a QLED device according to claim 37, wherein the hole transporting layer, the quantum dot emitting layer, and the electron transporting layer are deposited by a solution processing method or a vacuum evaporation method.
A method of fabricating a QLED device according to claim 9, comprising the steps of:

A, providing a substrate, forming a reflective cathode on the substrate;

B. sequentially depositing an electron transport layer, a quantum dot light emitting layer, and a hole transport layer on the reflective cathode;

C. Depositing a transparent anode on the hole transport layer to produce a reverse top emitting QLED device.
The method of producing a QLED device according to claim 39, wherein the hole transport layer, the quantum dot light-emitting layer, and the electron transport layer are deposited by a solution processing method or a vacuum evaporation method.
A method of fabricating a QLED device according to claim 13, comprising the steps of:

A, providing a substrate, forming a transparent cathode on the substrate;

B. sequentially depositing an electron transport layer, a quantum dot light emitting layer and a hole transport layer on the transparent cathode;

C. Depositing a reflective anode on the hole transport layer to obtain an inverted bottom emission QLED device.
The method of producing a QLED device according to claim 41, wherein the hole transporting layer, the quantum dot emitting layer, and the electron transporting layer are deposited by a solution processing method or a vacuum evaporation method.