WO2018120512A1

WO2018120512A1 - Quantum dot ink and preparation method therefor

Info

Publication number: WO2018120512A1
Application number: PCT/CN2017/080610
Authority: WO
Inventors: 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
Also published as: CN108276826B; CN108276826A

Abstract

A quantum dot ink, comprising the following components in percentage by weight: 0.01-40.0% of quantum dot, the quantum dot comprising at least one quantum dot structure unit arranged in a radial direction in sequence, and the quantum dot structure unit being a gradually-varied alloy component structure with energy level width varying in the radial direction or a uniform component structure with energy level width being consistent in the radial direction; and 60.0-99.99% of solvent, the solvent comprising at least one organic solvent. A preparation method for the quantum dot ink comprises: dispersing quantum dots in the solvent according to a formula and stirring for 20-40 minutes.

Description

Quantum dot ink and preparation method thereof

Technical field

The invention relates to the technical field of quantum dots, in particular to a quantum dot ink 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-based quantum dot electroluminescent diode devices (QLEDs) have been displaying image quality, device performance, and manufacturing by virtue of the characteristics and optimization of quantum dot nanomaterials. 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 quantum dots 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 dots of the existing classical structure system. The corresponding standard for the screening and optimization of quantum dots is basically from the luminescence properties of the quantum dots themselves, such as the luminescence peaks of quantum dots. Wide, solution quantum The yield and so on. The above quantum dots are directly applied to the QLED device structure to obtain corresponding device performance results.

However, QLED devices and corresponding display technologies as a complex optoelectronic device system, there will be many factors that will affect the performance of the device. Starting from a quantum dot as a 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 dots originally obtained in solution may show significant differences after forming solid films: for example, In the solid film, the wavelength of the luminescence peak will have different degrees of red shift (moving to long wavelengths), the width of the luminescence peak will become larger, and the quantum yield will be reduced to some extent, that is, the excellent luminescence properties of quantum dots in solution. It cannot be fully inherited into the quantum dot solid film of QLED devices. Therefore, in designing and optimizing the structure and synthetic formulation of quantum dots, it is necessary to simultaneously consider the optimization of the luminescence properties of the quantum dots themselves and the maximization of the luminescence properties of the quantum dots in the state of the solid film.

Secondly, the luminescence of quantum dots 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 in quantum After the point luminescent layer is combined, the 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 the luminescence efficiency, only affect the efficiency of the radiation transition in the above process, and the overall luminescence efficiency of the QLED device is simultaneously affected by the charge injection of holes and electrons in the quantum dots in the above process. And the effect of transmission efficiency, relative charge balance of holes and electrons in quantum dots, recombination of holes and electrons in quantum dots, and the like. Therefore, in designing and optimizing the structure of quantum dots, 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, fine energy of quantum dots. 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 dots 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 based on the improvement of the self-luminous properties of quantum dots can not meet the comprehensive requirements of QLED devices and corresponding display technologies for optical properties, electrical properties, processing performance and other aspects. It is necessary to tailor the fine core-shell structure, composition and energy level of quantum dots for the requirements of QLED devices and corresponding display technologies.

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 dots 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 with 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 7,919,012B2), 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.

Although the quantum dots of the core-shell structure described above partially improve the performance of the quantum dots, both the design idea and the optimization scheme are based on the improvement of the luminous efficiency of the quantum dots themselves. Its luminescence properties have yet to be improved, and other special requirements for other aspects of quantum dots in semiconductor devices have not been comprehensively considered.

Dispersing quantum dots in a specific solvent can form corresponding quantum dot inks, and quantum dot inks are the most common direct method for the application of special nanomaterials such as quantum dots to industrial production methods, such as inkjet printing, transfer printing, Screen printing, spin coating, filling and other solution processes to achieve industrial applications of quantum dot inks; such as Drop on Demand, similar to Inkjet Printing, can be precisely tailored to the needs The quantum dots are deposited at a set position to form a precision pixel film, which can effectively solve the manufacturing problem of the large-size color QLED screen and reduce the cost. However, different solution processes have different requirements for quantum dot inks. It is usually necessary to adjust ink parameters such as viscosity, surface tension and boiling point to ensure the dispersion solubility and colloidal stability of quantum dots in the ink system. The prepared quantum dot ink has good processability and inherits the original excellent performance of quantum dots.

The quantum dots are usually dispersed in a solvent such as a short carbon paraffin or a monocyclic aromatic hydrocarbon, such as a solvent such as octane, hexane or toluene. These organic solvents have relatively low viscosity, and the viscosity is lower than 1 cP at room temperature, and the surface tension is high. Also relatively low. Quantum dot inks using such low viscosity solvents have poor processability and cannot meet the basic requirements of production processes such as inkjet printing. There is therefore a need to develop new solvent systems to form quantum dot inks with processability. At present, several companies have reported quantum dot inks for inkjet printing:

Nanoco Technologies Ltd, UK, discloses a method of printing a printable ink formulation comprising nanoparticles (CN101878535B). By selecting a suitable ink substrate, such as toluene and dodecanol, a printable nanoparticle ink and corresponding nanoparticle-containing film are obtained.

South Korea's Samsung Electronics has disclosed a quantum dot ink (US8765014B2) for inkjet printing. This ink contains a concentration of quantum dots, an organic solvent, and an alcohol polymer additive having a high viscosity. The preparation of quantum dot films and quantum dot electroluminescent devices is achieved based on such inks.

US QD Vision, Inc. discloses a quantum dot ink formulation comprising a host material, A quantum dot and an additive (US2010264371A1).

Other patents relating to quantum dot printing inks are: US2008277626A1, US2015079720A1, US2015075397A1, TW201340370A, US2007225402A1, US2008169753A1, US2010265307A1, US2015101665A1, WO2008105792A2. In these published patents, in order to regulate the physical parameters of the ink, these quantum dot inks contain other additives such as alcohol polymers. However, polymer additives with insulating properties are not easily removed, and the introduction of such polymer additives tends to reduce the charge transport capability of the film and has a negative impact on the photovoltaic performance of the device.

So far, the disclosed quantum dot inks have been developed based on existing or classical quantum dots for related ink formulations and preparation methods, and have not been combined with practical application fields and requirements of corresponding quantum dot inks, for example, The inkjet printing technology in the printing display technology tailors the quantum dots themselves, so that the quantum dot ink can achieve excellent processing performance while achieving excellent performance requirements for display applications such as optics and electricity.

The quantum dot ink used in semiconductor devices not only needs to achieve the good processability of the corresponding ink through the selection and optimization of the solvent system, especially the printability, but more importantly, it is also necessary to consider the processing of the quantum dot ink to form a semiconductor device for quantum dots. In the comprehensive requirements of optical performance, electrical performance and other aspects, it is necessary to tailor the fine core-shell structure, composition and energy level of quantum dot luminescent materials for the requirements of semiconductor devices and corresponding display technologies. Therefore, in addition to the development of a good solvent system, the development of high-performance quantum dot inks for semiconductor devices is also very important. The solvent system will affect the printability and final film formation of quantum dot inks, and the quantum dot performance will directly affect the device performance of the quantum dot film after film formation.

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

Summary of the invention

In view of the above deficiencies of the prior art, an object of the present invention is to provide a quantum dot ink and a preparation method thereof, which are intended to solve the processability and film formability of a solvent system for a conventional semiconductor device. It can not meet the requirements, and the performance of the device after the quantum dot film used in the conventional semiconductor device is reduced.

The technical solution of the present invention is as follows:

A quantum dot ink comprising, by weight percent, the following components:

Quantum dot: 0.01-40.0%; the quantum dot includes at least one quantum dot structural unit sequentially arranged in a radial direction, the quantum dot structural unit being 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;

Solvent: 60.0 to 99.99%; the solvent contains at least one organic solvent.

The quantum dot ink, wherein the solvent comprises decalin, dodecane, 2-methylcyclohexanol, o-dichlorobenzene, phenylcyclohexane, ethylene glycol monobutyl ether and diethylene glycol One or more of the alcohol ethers.

The quantum dot ink, wherein the solvent comprises 1-3 kinds of organic solvents.

The quantum dot ink, wherein the quantum dot accounts for 0.5-10% by weight of the quantum dot ink.

The quantum dot ink, wherein the quantum dot ink has a boiling point ranging from 50 ° C to 300 ° C.

The quantum dot ink, wherein the quantum dot ink has a boiling point ranging from 120 ° C to 200 ° C.

The quantum dot ink, wherein the quantum dot ink has a viscosity ranging from 0.5 cPs to 40 cPs.

The quantum dot ink, wherein the quantum dot ink has a viscosity ranging from 2.0 cPs to 20 cPs.

The quantum dot ink, wherein the quantum dot ink has a surface tension ranging from 20 to 50 mN/m.

The quantum dot ink, wherein the quantum dot ink has a surface tension ranging from 25 to 35 mN/m.

In the quantum dot ink, wherein 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 of the quantum dot structural unit adjacent in the radial direction The level is continuous.

The quantum dot ink, wherein the quantum dot comprises at least three quantum dot structural units arranged in a radial direction, wherein the at least three quantum dot structural units are located The quantum dot structural unit of the center and the surface 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 of the gradient alloy composition adjacent in the radial direction It is continuous; a quantum dot structural unit located between the central and surface quantum dot structural units is a homogeneous composition structure.

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

In the quantum dot ink, wherein 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 quantum dot ink, wherein 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. .

The quantum dot ink, wherein the quantum dot comprises two quantum dot structural units, wherein one quantum dot structural unit is a graded alloy composition structure in which a width of the outer energy level is wider in the radial direction, and the other The quantum dot structural unit is a homogeneous component structure, and the interior of the quantum dot includes one or more quantum dot structural units of a graded alloy composition structure, and quantum dots of a graded alloy composition structure adjacent in a radial direction The energy levels of the structural units are continuous; the exterior of the quantum dots includes one or more quantum dot structural units of a uniform composition structure.

The quantum dot ink, wherein the quantum dot 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 an outer energy level in a radial direction. The wider the width of the graded alloy component structure, the interior of the quantum dot includes one or more quantum dot structural units of a uniform composition structure, and the outer portion of the quantum dot 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 quantum dot ink, wherein the quantum dot structural unit is a graded alloy component structure or a uniform alloy component structure comprising a group II and group VI element.

The quantum dot ink, wherein each of the quantum dot structural units comprises 2-20 layer monoatomic layers, or each quantum dot structural unit comprises 1-10 layer cell layers.

The quantum dot ink, wherein the quantum dot has an emission peak wavelength ranging from 400 nm to 700 nm.

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

A method for preparing a quantum dot ink according to any one of the preceding claims, comprising the steps of: first dispersing a quantum dot in a solvent according to the above formula, and then stirring for 20 to 40 minutes to obtain a quantum dot ink, wherein the quantum dot And including at least one quantum dot structural unit sequentially arranged in a radial direction, wherein the 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 energy level width in a radial direction a substructure; the solvent comprises at least one organic solvent.

The method for preparing a quantum dot ink, wherein the method for preparing the quantum dot 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.

Advantageous Effects: The present invention selects the above solvent system, and can achieve good film forming performance and processability of the quantum dot ink, especially printability. In addition, the present invention selects the above quantum dots, and the semiconductor device formed after film formation has excellent device performance.

DRAWINGS

1 is a graph showing the energy level structure of a quantum dot specific structure 1 of the present invention.

2 is a graph showing the energy level structure of a quantum dot specific structure 2 of the present invention.

3 is a graph showing the energy level structure of a quantum dot specific structure 3 of the present invention.

4 is a graph showing the energy level structure of a quantum dot specific structure 4 of the present invention.

FIG. 5 is a graph showing the energy level structure of a quantum dot specific structure 5 of the present invention.

FIG. 6 is a graph showing the energy level structure of a quantum dot specific structure 6 of the present invention.

FIG. 7 is a graph showing the energy level structure of a quantum dot specific structure 7 of the present invention.

FIG. 8 is a schematic structural view of a quantum dot light emitting diode according to Embodiment 37 of the present invention.

FIG. 9 is a schematic structural view of a quantum dot light emitting diode according to Embodiment 38 of the present invention.

FIG. 10 is a schematic structural view of a quantum dot light emitting diode according to Embodiment 39 of the present invention.

11 is a schematic structural view of a quantum dot light emitting diode according to Embodiment 40 of the present invention.

12 is a schematic structural view of a quantum dot light emitting diode according to Embodiment 41 of the present invention.

FIG. 13 is a schematic structural view of a quantum dot light emitting diode according to Embodiment 42 of the present invention.

detailed description

The present invention provides a quantum dot ink and a preparation method thereof, and the present invention will be further described in detail below in order to make the objects, technical solutions and effects of the present invention more clear and clear. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The present invention provides a quantum dot ink comprising, by weight percentage, a composition comprising: quantum dots: 0.01-40.0%; the quantum dots comprising at least one quantum dot structural unit arranged in a radial direction. The quantum dot structural 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; the solvent: 60.0‐99.99%; the solvent contains at least one organic Solvent. The invention adopts the above solvent system, and can realize good film forming performance and processability of the quantum dot ink, especially printability. In addition, this hair The above quantum dots are selected, and the semiconductor device formed after film formation has excellent device performance.

Preferably, the solvent of the present invention comprises 1-3 kinds of organic solvents. For example, the solvent of the present invention may be a solvent of decalin, which may be two solvents of dodecane and 2-methylcyclohexanol, and may be o-dichlorobenzene, phenylcyclohexane and 2-methyl. The three solvents of cyclohexanol may also be three solvents of ethylene glycol monobutyl ether and diethylene glycol diethyl ether.

Preferably, the quantum dot accounts for 0.5-10% by weight of the quantum dot ink, for example, the quantum dot accounts for 5% by weight of the quantum dot ink.

Specifically, the quantum dot ink of the present invention has a boiling point in the range of 50 ° C - 300 ° C, and a preferred quantum dot ink has a boiling point in the range of 120 ° C - 200 ° C.

Specifically, the viscosity of the quantum dot ink of the present invention ranges from 0.5 cPs to 40 cPs at room temperature conditions (25 ° C), and the viscosity of the preferred quantum dot ink ranges from 2.0 cPs to 20 cPs.

Specifically, the surface tension of the quantum dot ink of the present invention ranges from 20 to 50 mN/m under room temperature conditions (25 ° C), and the preferred surface tension of the quantum dot ink ranges from 25 to 35 mN/m.

The quantum dot provided by the present invention comprises at least one quantum dot structural unit sequentially arranged in a radial direction, wherein the quantum dot structural unit is a graded alloy composition structure or a radial direction in which a width of the energy level changes in a radial direction. A uniform composition structure with uniform upper level.

That is to say, in the quantum dots provided by the present invention, each quantum dot structural unit has an alloy within a single atomic layer or more than one layer of a single atomic layer at any position in the radial direction from the inside to the outside. The structure of the components.

Further, in 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 at the same time and 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 here refers to the direction from the center of the quantum dot, for example, assuming that the quantum dot of the present invention is a spherical or spherical-like structure, then the radial direction refers to the center of the quantum dot in the direction of the radius (or Internal) refers to the center of its physical structure, and the surface (or exterior) of a quantum dot refers to the surface of its physical structure.

The structure of the quantum dots of the present invention will be described in detail below:

Specifically, as shown in FIG. 1 , the present invention provides a quantum dot having a funnel-type energy level structure, and a quantum dot structure unit alloy component located inside the quantum dot has a corresponding energy level width smaller than a quantum dot structure located outside. The unit alloy composition component corresponds to the energy level width; specifically, the quantum dot 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 is radially outward in the radial direction. The graded alloy composition structure has a wider 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 structure of the quantum dot shown in FIG. 1 in the subsequent embodiment Called the specific structure 1. In the quantum dot in FIG. 1, 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, that is, a mutant structure, that is, The alloy composition of the quantum dots is 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, in the quantum dot The width of the energy level 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 energy level structure shown in FIG. 1 is from the center of the quantum dot to The energy levels of the quantum dot surface are continuous. Meanwhile, in the quantum dots 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 a continuously changing characteristic, which is more advantageous for achieving high light emission. effectiveness.

That is, the specific structure 1 of the quantum dots has a radial direction from the inside to the outside. The quantum dot structure of the continuous graded alloy composition; the quantum dot structure has a continuous change in composition from the inside to the outside in the radial direction; correspondingly, the energy level distribution also has an inner to outer diameter The characteristic of continuous change in direction; the characteristic that the quantum dot structure continuously changes in composition and energy level distribution, and the quantum dot of the present invention is not only beneficial to realize more than the relationship between the quantum dot core and the shell having a clear boundary. Efficient luminous efficiency, but also better meet the comprehensive performance requirements of quantum devices and corresponding display technologies for quantum dots. It is an ideal quantum dot luminescent material suitable for semiconductor devices and display technologies.

Further, in the quantum dots provided in Fig. 1, 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 than point B, and the composition of point A and point B satisfies: _x0 ^A > _x0 ^B , _y0 ^A > _y0 ^B . That is to say, for any two points in the quantum dot, point A and point B, and point A is closer to the center of the quantum point relative to point B, then _x0 ^A > _x0 ^B , _y0 ^A > _y0 ^B , that is, the Cd content of point A The Cd content greater than 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, a gradation structure is formed in the radial direction, and the lower the Cd and Se contents are, the more outward (i.e., away from the center of the quantum dot) in the radial direction, the more the Zn and S contents are. High, then according to the characteristics of these elements, the width of the energy level will be wider.

In the subsequent quantum dots of different specific structures, if 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, the 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 relative to 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, and the composition of point C and point D satisfies: _x0 ^C < _x0 ^D , _y0 ^C < _y0 ^D . If the quantum dot structural unit is a uniform alloy component structure (i.e., 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, and the composition of point E and point F satisfies: _x0 ^E = _x0 ^F , _y0 ^E = _y0 ^F .

Further, as shown in FIG. 2, 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 of a quantum dot structural unit of a homogeneous alloy composition structure; that is, the quantum dot provided by the present invention includes at least three quantum dot structural units arranged in a radial direction, wherein the at least three quantum In the dot structure unit, the quantum dot structural unit located at the center and the surface is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the quantum structure of the graded alloy component adjacent in the radial direction is quantum. The energy level of the point 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 shown in FIG. 2 is referred to as a specific structure 2 in the subsequent embodiments.

Specifically, in the quantum dots provided in FIG. 2, 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, among the quantum dots provided in FIG. 2, 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 adjacent gradients in the radial direction. The energy level of the quantum dot structural unit of the alloy component structure is continuous; that is, in the quantum dot structural unit having the structure of the graded alloy component, the energy level corresponding to the alloy composition at any point in the radial direction is An energy level width corresponding to an alloy composition that is adjacent to and closer to another point in the center of the quantum dot structure. 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. 3, the present invention also provides a quantum dot having a fully graded alloy composition of a quantum well structure; that is, the quantum dot 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 has a larger outer diameter level in the radial direction. A narrow graded alloy composition structure in which 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 to say, the quantum dot structure unit distribution of the quantum dots may be: A1, A2, A1, A2, A1, ..., or A2, A1, A2, A1, A2, ..., that is, the initial quantum dot structural unit. It can be of type A1 or 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 shown in FIG. 3 is referred to as a specific structure 3 in the subsequent embodiment.

Further, as shown in FIG. 4, the present invention also provides a quantum dot of an alloy composition of a quantum well structure having a sudden change in energy level. Specifically, the quantum dot structural unit has a width in the radial direction. The wider the gradient alloy composition 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, 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 dots shown in FIG. 4 is referred to as a specific structure 4.

Specifically, the quantum dots described in FIG. 4 are sequentially arranged by a plurality of quantum dot structural units by means of abrupt changes, and the quantum dot structural units are all in the radial direction. Wide graded alloy component structure. Further, in the quantum dots, 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 to say, in the quantum dots, the width of the energy level 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, the quantum dots are not The method is limited to the above manner, that is, the energy level width of the quantum dot structural unit away 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 widths of adjacent quantum dot structural units are staggered. The place.

Further, as shown in FIG. 5, the present invention also provides another quantum dot of an alloy composition of a quantum well structure having a sudden change in energy level. Specifically, the quantum dot structural unit has an outer level in the radial direction. The narrower the width of the gradient alloy composition 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, 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 dots shown in FIG. 5 is referred to as a specific structure 5.

Specifically, the quantum dots described in FIG. 5 are sequentially arranged by a plurality of quantum dot structural units by abrupt changes, and the quantum dot structural units are all graded alloy groups in which the width of the outer energy level is narrower in the radial direction. Substructure. Further, in the quantum dots, 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 dots, 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, the quantum dots are not The method is 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 widths of adjacent quantum dot structural units are staggered. The place.

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

Specifically, in the quantum dots shown in FIG. 6, the distribution of the quantum dot structural units is A3...A3A4...A4, that is, the inside of the quantum dots is composed of A3 type quantum dot structural units, the quantum dots The outer portion 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 one.

Further, as shown in FIG. 7, the present invention further provides another quantum dot, wherein the alloy composition inside the quantum dot has a uniform energy level width, and the energy level width of the alloy composition outside the quantum dot is uniform. From the center to the outside, it gradually becomes larger; specifically, the quantum dot includes two kinds of quantum dot structural units (A5 type and A6 type), wherein the A5 type quantum dot structural unit is a uniform alloy composition structure, and the A6 type 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 inside of the quantum dot includes one or more quantum dot structural units of a uniform alloy composition structure; the quantum dot The outer portion 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; in subsequent embodiments The structure of the quantum dots shown in Fig. 7 is referred to as a specific structure 7.

Specifically, in the quantum dots shown in FIG. 7, the distribution of the monoatomic layers is A5...A5A6...A6, that is, the inside of the quantum dots is composed of A5 type quantum dot structural units, and the outside of the quantum dots It 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 quantum The point achieves 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 present invention adopts the quantum dots of the above structure, and can realize the luminescence quantum yield ranging from 1% to 100%, and the preferred luminescence quantum yield ranges from 30% to 100%, and the quantum dot can be ensured within the preferred luminescence quantum yield range. Good applicability.

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

The quantum dots 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 quantum dots here. A luminescence quantum yield of greater than 30% is achieved in the range.

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

The quantum dots provided by the invention have 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, The luminous efficiency of quantum dots is improved. Secondly, the energy level structure formed by the quantum dots provided by the invention is more favorable for the effective binding of electron clouds in the quantum dots, greatly reducing the probability of diffusion of the surface of the electron cloud vector sub-points, thereby greatly suppressing the quantum dots without radiation. The Auger recombination loss of the transition reduces the quantum dot flicker and improves the luminous efficiency of the quantum dots. Thirdly, the energy level structure formed by the quantum dots provided by the invention is more advantageous for improving the injection efficiency and transmission efficiency of the quantum dot light-emitting layer charge in the semiconductor device; and at the same time, the charge accumulation and the resulting exciton quenching can be effectively avoided. Off. Fourth, the easily controllable diversity energy formed by the quantum dots provided by the present invention The stage structure can fully satisfy and match the energy level structure of other functional layers in the device to achieve the matching of the overall energy level structure of the device, thereby contributing to the realization of an efficient semiconductor device.

The present invention further provides a method for preparing a quantum dot ink according to any of the above, comprising the steps of: first dispersing a quantum dot in a solvent according to the above formula, and then stirring for 20-40 minutes to obtain a quantum. a dot ink; the quantum dot comprising at least one quantum dot structural unit sequentially arranged in a radial direction, the quantum dot structural unit being a graded alloy composition structure or a radial direction in which a width of the energy level changes in a radial direction A uniform composition structure having uniform energy levels; the solvent comprising at least one organic solvent.

The quantum dot ink obtained by the present invention has good film forming properties and workability, particularly printability. Moreover, the QLED device made of the quantum dot ink of the present invention has excellent optical and electrical properties.

Specifically, the present invention also provides a method for preparing a quantum dot as described above, comprising the steps of:

Synthesizing the first compound at a predetermined position;

A cation exchange reaction occurs between the first compound and the second compound to form a quantum dot, 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 quantum dot SILAR synthesis method and quantum dot one-step synthesis method to generate quantum dots, in particular, using quantum dot layer-by-layer growth and quantum dot one-step synthesis method to form a 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 appears blue shift, it indicates that the luminescence peak shifts toward the short wavelength direction, and the energy level width becomes wider; when the luminescence peak wavelength of the quantum dot appears red shift, the generation The luminescence peak of the table moves toward the long wave direction, and the energy level width is narrowed; when the luminescence peak wavelength of the quantum dot is constant, the energy level width 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 At least one of Zinc oleate or Zinc stearate, etc., but is not limited thereto.

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‐TOA ( At least one of selenium-trioctylamine), Se‐ODPA (selenium‐octadecylphosphonic acid) or Se‐OLA (selenium‐oleylamine), and the like, 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 mercaptan is hexanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol or At least one of mercaptopropylsilane or the like 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; When it is necessary to synthesize a nanocrystal of Cd _x Zn _{1 -x} Se, a precursor of Cd, a precursor of Zn, and a precursor of Se are required.

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. Thickness range and extent of cation exchange The formation of the graded alloy composition formed is determined. 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 ensures that the reaction rate is within an easily controllable range.

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

The quantum dots prepared by the above preparation method have a luminescence quantum yield ranging from 1% to 100%, and the preferred luminescence quantum yield ranges from 30% to 100%, and the preferred luminescent quantum yield range can ensure good application of quantum dots. Sex.

In addition to preparing the quantum dots of the present invention according to the above preparation method, the present invention also provides another method for preparing quantum dots 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 quantum dots, And the luminescence peak wavelength of the quantum dot exhibits one or more of blue shift, red shift, and invariance during the reaction, thereby realizing distribution of the alloy composition at a predetermined position.

The difference between this 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 achieve the distribution of the alloy components required by the present invention, and the latter method is directly controlled at a predetermined position. a cationic precursor to which the desired synthetic alloy component is added The anion precursor is reacted to form quantum dots to achieve 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. The reaction temperature, the reaction time, the ratio, and the like may be different depending on the specific quantum dots to be synthesized, which are substantially the same as the former method described above, and will be described later in the specific examples.

The present invention also provides a semiconductor device comprising the quantum dot ink of any of the above.

The semiconductor device is any one of an electroluminescent device, a photoluminescence device, a solar cell, a display device, a photodetector, a bioprobe, and a nonlinear optical device.

Taking an electroluminescent device as an example, the quantum dot ink of the present invention is used as a quantum dot electroluminescent device of a light-emitting layer material. Such quantum dot electroluminescent devices are capable of achieving: 1) high efficiency charge injection, 2) high luminance, 3) low drive voltage, 4) high device efficiency and the like. At the same time, the quantum dots of the present invention have the characteristics of easy control and multi-level structure, and 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 A highly efficient and stable semiconductor device is realized.

The photoluminescent device refers to a device that relies on an external light source to obtain energy, thereby generating excitation and causing light emission, and ultraviolet radiation, visible light, and infrared radiation can cause photoluminescence, such as phosphorescence and fluorescence. The nanocrystal of the present invention can be used as a light-emitting material of a photoluminescent device.

The solar cell is also called a photovoltaic device, and the nanocrystal of the invention can be used as a light absorbing material of a solar cell, thereby effectively improving various performances of the photovoltaic device.

The display device refers to a backlight module or a display panel to which the backlight module is applied, and the display panel can be applied to various products, such as a display, a tablet, a mobile phone, a notebook computer, a flat-panel TV, and a wearable display. Equipment or other products that contain different sized display panels.

The photodetector refers to a device capable of converting an optical signal into an electrical signal, the principle of which is The radiation causes the conductivity of the irradiated material to change, and the quantum dot is applied to the photodetector. It has the following advantages: sensitivity to normal incident light, high photoconductivity, high detection ratio, continuous detection wavelength, and low temperature preparation. . During operation of the photodetector of such a structure, the photogenerated electron-hole pairs generated by the quantum dot photosensitive layer (ie, using the nanocrystal of the present invention) can be separated by the built-in electric field, which makes the photodetector The structured photodetector has a lower drive voltage and can operate with low applied bias or even 0 applied bias and is easy to control.

The bioprobe refers to a device that modifies a certain type of material to have a labeling function, for example, coating the nanocrystal of the present invention to form a fluorescent probe, which is used in the field of cell imaging or substance detection, as opposed to The traditional organic fluorescent dye probe adopts the biological probe prepared by the nanocrystal of the invention, and has the characteristics of high fluorescence intensity, good chemical stability and strong anti-photobleaching ability, and has wide application.

The nonlinear optical device belongs to the field of optical laser technology and is widely used, for example, for electro-optic light-on and laser modulation, for laser frequency conversion, laser frequency tuning, optical information processing, image quality improvement and beam quality; As a nonlinear etalon and bistable device; study the high-excited state of the material as well as the high-resolution spectrum and the internal energy and excitation transfer process of the material and other relaxation processes.

The invention is further illustrated by the following examples (wt% is by weight).

Example 1: The formulation and preparation process of the quantum dot ink is as follows:

The solvent consists of a solvent such as decalin.

The following components were added to a 500 mL single-necked flask with uniform stirring in the order of 100 mg of quantum dots (surface ligand was oleic acid), 10 mL of decalin, and the mixture was stirred for 30 minutes to obtain a quantum dot ink.

Example 2: The formulation and preparation process of the quantum dot ink is as follows:

The mixed solvent is composed of two solvents, dodecane and 2-methylcyclohexanol, wherein the volume ratio of dodecane to 2-methylcyclohexanol is 1:1.

Add the following components to a 500 mL single-mouth flask with uniform agitation, in order of addition To be: 100 mg of quantum dots (surface ligand is octyl mercaptan), 2.5 mL of dodecane solvent, 2.5 mL of 2-methylcyclohexanol solvent, and the mixture was stirred for 30 minutes to obtain a quantum dot ink.

Example 3: The formulation and preparation process of the quantum dot ink is as follows:

The mixed solvent is composed of o-dichlorobenzene, phenylcyclohexane and 2-methylcyclohexanol, wherein the volume ratio of o-dichlorobenzene, phenylcyclohexane and 2-methylcyclohexanol is 1 :4:5.

The following components were added to a 500 mL single-necked flask with uniform stirring in the order of: 100 mg of quantum dots (surface ligand is oleic acid), 0.3 mL of o-dichlorobenzene solvent, 1.2 mL of phenylcyclohexane An alkane solvent, 1.5 mL of a 2-methylcyclohexanol solvent, and the mixture was stirred for 30 minutes to obtain a quantum dot ink.

Example 4: The formulation and preparation process of the quantum dot ink is as follows:

The mixed solvent is composed of two solvents of ethylene glycol monobutyl ether and diethylene glycol diethyl ether, wherein the volume ratio of ethylene glycol monobutyl ether to diethylene glycol diethyl ether is 2:3.

The following components were added to a 500 mL single-necked flask with uniform stirring in the order of: 100 mg of quantum dots (surface ligand is PEG), 2.0 mL of ethylene glycol monobutyl ether solvent, 3.0 mL of diethylene glycol The alcohol ether solvent was stirred and the mixture was stirred for 30 minutes to obtain a quantum dot ink.

Example 5: 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 6: 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 7: 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. Therefore, a graded alloy composition distribution of Cd content and Zn content is formed near the interface between the Cd _y Zn _1‐y Se layer and the Cd _z Zn _1‐z Se layer, that is, Cd _x Zn _1‐x Se, where 0≤x ≤1.

Example 8: 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 9: 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 is gradually decreased along the radial direction, and the Zn content is gradually decreased. 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 10: 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 11: 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 12: 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 13: 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 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 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 14: Preparation of Blue Quantum Dots with Concrete 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, until the reaction mixture was cooled to room temperature, toluene and the product was again dissolved in anhydrous methanol, the precipitate is then purified by centrifugation, to give a blue quantum dots _{_{(Cd x Zn 1-x S}} ) having a specific structure 1.

Example 15: 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 16: Preparation of Red Quantum Dots with Concrete 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 17: 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 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 blue quantum dot (Cd _x Zn _{1 -x} S/Cd _y Zn) having a specific structure 1. _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 18: Effect of cadmium oleate injection on the synthesis of blue quantum dots with specific structure 1

On the basis of Example 14 and Example 17, by adjusting the injection amount of the cadmium oleate precursor, the interval of the gradient change of the composition of the quantum dot can be controlled, thereby affecting the change of the energy level structure, and finally realizing the quantum dot luminescence. Wavelength regulation. 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 19: 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 20: 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.

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 to reflux at 250 ° C under a nitrogen atmosphere. At 120 min, a transparent cadmium oleate precursor was obtained.

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 21: Preparation of Red Quantum Dots with Concrete 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 22: Preparation of blue quantum dots with specific structure 3

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 23: 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 and 0.3 mmol of sulfur powder (Sulfur powder) were dissolved in 2 mL of Trioctylphosphine to obtain trioctylphosphine selenide-trioctylphosphine sulfide 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 24: Preparation of red quantum dots with specific structure 3

0.9 mmol of cadmium oxide (CdO), 0.9 mL of oleic acid (Oleic acid) and 8.1 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 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 25: 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 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 20 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 blue quantum dot (CdZnS/CdZnSe/) having a quantum well level structure (specific structure 4). CdZnS).

Example 26: 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 27: 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 to reflux at 250 ° C under a nitrogen atmosphere. At 120 min, a transparent cadmium oleate precursor was obtained.

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 28: 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 29: Preparation of green 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 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 30: 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 31: 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.

Dissolve 6mmol of sulfur powder (Sulfur powder) in 3mL of trioctylphosphine In (Trioctylphosphine), a trioctylphosphine sulfide precursor is obtained.

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 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 blue quantum dot (Cd _x Zn _{1 - x} S) having a specific structure 6.

Example 32: 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 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 of 6 (Cd _x Zn _{1 -x} Se _y S _1‐y /ZnS).

Example 33: Preparation of red 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 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 34: 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 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 completely injected into the reaction system. Subsequently, 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 35: 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.

2mmol sulfur powder (Sulfur powder) and 1.6mmol selenium powder (Selenium powder) 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 36: Preparation of red quantum dots with specific structure 7

Preparation of cadmium oleate precursor: 0.8 mmol of cadmium oxide (CdO), 4 mL of oleic acid (Oleic acid) and 10 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.

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 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 quantum well energy. Graded structure of red fluorescent quantum dots.

Example 37

The quantum dot light emitting diode of this embodiment, as shown in FIG. 8, includes, in order from bottom to top, an ITO substrate 11, a bottom electrode 12, a PEDOT: PSS hole injection layer 13, a poly-TPD hole transport layer 14, and a quantum dot. The light-emitting layer 15, the ZnO electron transport layer 16, and the Al top electrode 17.

The preparation steps of the above quantum dot light emitting diode are as follows:

After sequentially preparing the bottom electrode 12, the 30 nm PEDOT:PSS hole injection layer 13 and the 30 nm poly-TPD hole transport layer 14 on the ITO substrate 11, a quantum dot light-emitting layer is prepared on the poly-TPD hole transport layer 14. 15. The thickness was 20 nm, and then a 40 nm ZnO electron transport layer 16 and a 100 nm Al top electrode 17 were prepared on the quantum dot light-emitting layer 15. The material of the quantum dot light-emitting layer 15 is a quantum dot ink as described in the examples.

Example 38

In the present embodiment, the quantum dot light-emitting diodes, as shown in FIG. 9, include, in order from bottom to top, an ITO substrate 21, a bottom electrode 22, a PEDOT: PSS hole injection layer 23, and a poly(9-vinylcarbazole) (PVK) space. The hole transport layer 24, the quantum dot light-emitting layer 25, the ZnO electron transport layer 26, and the Al top electrode 27.

After sequentially preparing the bottom electrode 22, the 30 nm PEDOT:PSS hole injection layer 23 and the 30 nm PVK hole transport layer 24 on the ITO substrate 21, a quantum dot light-emitting layer 25 is prepared on the PVK hole transport layer 24, and the thickness is At 20 nm, a 40 nm ZnO electron transport layer 26 and a 100 nm Al top electrode 27 were subsequently prepared on the quantum dot light-emitting layer 25. The material of the quantum dot light-emitting layer 25 is a quantum dot ink as described in the examples.

Example 39

The quantum dot light emitting diode of this embodiment, as shown in FIG. 10, includes an ITO substrate 31, a bottom electrode 32, a PEDOT: PSS hole injection layer 33, a poly-TPD hole transport layer 34, and a quantum dot in this order from bottom to top. The light-emitting layer 35, the TPBi electron transport layer 36, and the Al top electrode 37.

After sequentially preparing the bottom electrode 32, the 30 nm PEDOT:PSS hole injection layer 33 and the 30 nm poly-TPD hole transport layer 34 on the ITO substrate 31, a quantum dot light-emitting layer is prepared on the poly-TPD hole transport layer 34. 35, a thickness of 20 nm, and then a 30 nm TPBi electron transport layer 36 and a 100 nm Al top electrode 37 were prepared by vacuum evaporation on the quantum dot light-emitting layer 35. The material of the quantum dot light-emitting layer 35 is a quantum dot ink as described in the examples.

Example 40

The quantum dot light-emitting diode of this embodiment, as shown in FIG. 11, includes an ITO substrate 41, a bottom electrode 42, a ZnO electron transport layer 43, a quantum dot light-emitting layer 44, an NPB hole transport layer 45, and a MoO in this order from bottom to top. ₃ hole injection layer 46 and Al top electrode 47.

A bottom electrode 42 and a 40 nm ZnO electron transport layer 43 are sequentially prepared on the ITO substrate 41, and a quantum dot light-emitting layer 44 is formed on the ZnO electron transport layer 43 to a thickness of 20 nm, and then a 30 nm NPB space is prepared by a vacuum evaporation method. The hole transport layer 45, the ₅ nm MoO ₃ hole injection layer 46 and the 100 nm Al top electrode 47. The material of the quantum dot light-emitting layer 44 is a quantum dot ink as described in the examples.

Example 41

The quantum dot light-emitting diode of this embodiment, as shown in FIG. 12, includes, in order from bottom to top, a glass substrate 51, an Al electrode 52, a PEDOT: PSS hole injection layer 53, a poly-TPD hole transport layer 54, and a quantum dot. The light-emitting layer 55, the ZnO electron transport layer 56, and the ITO top electrode 57.

A 100 nm Al electrode 52 was prepared on the glass substrate 51 by a vacuum evaporation method, and then a 30 nm PEDOT:PSS hole injection layer 53 and a 30 nm poly-TPD hole transport layer 54 were sequentially prepared, followed by a poly-TPD hole transport layer 54. A quantum dot light-emitting layer 55 was prepared to have a thickness of 20 nm, and then a 40 nm ZnO electron transport layer 56 was prepared on the quantum dot light-emitting layer 55. Finally, 120 nm of ITO was prepared as a top electrode 57 by a sputtering method. The material of the quantum dot light-emitting layer 55 is a quantum dot ink as described in the examples.

Example 42

The quantum dot light emitting diode of this embodiment, as shown in FIG. 13, includes a glass substrate 61, an Al electrode 62, a ZnO electron transport layer 63, a quantum dot light emitting layer 64, an NPB hole transport layer 65, and a MoO. ₃ hole injection layer 66 and ITO top electrode 67.

A 100 nm Al electrode 62 is prepared on the glass substrate 61 by a vacuum evaporation method, and then a 40 nm ZnO electron transport layer 63, a 20 nm quantum dot light emitting layer 64 is sequentially prepared, and then a 30 nm NPB hole transport layer 65 is prepared by a vacuum evaporation method. 5 nm MoO ₃ hole injection layer 66, and finally 120 nm ITO was prepared as a top electrode 67 by a sputtering method. The material of the quantum dot luminescent layer is a quantum dot ink as described in the examples.

In summary, the present invention provides a quantum dot ink and a preparation method thereof. The present invention selects the above solvent system, and can achieve good film forming performance and processability of the quantum dot ink, especially printability. In addition, the present invention selects the above quantum dots, and the semiconductor device formed after film formation has excellent device performance.

It is to be understood that the application of the present invention is not limited to the above-described examples, and those skilled in the art can make modifications and changes in accordance with the above description, all of which are within the scope of the appended claims.

Claims

A quantum dot ink characterized by comprising the following components in percentage by weight:

Quantum dot: 0.01-40.0%; the quantum dot includes at least one quantum dot structural unit sequentially arranged in a radial direction, the quantum dot structural unit being 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;

Solvent: 60.0 to 99.99%; the solvent contains at least one organic solvent.
The quantum dot ink according to claim 1, wherein the solvent comprises decalin, dodecane, 2-methylcyclohexanol, o-dichlorobenzene, phenylcyclohexane, and ethylene glycol. One or more of butyl ether and diethylene glycol diethyl ether.
The quantum dot ink according to claim 1, wherein the solvent comprises 1-3 kinds of organic solvents.
The quantum dot ink according to claim 1, wherein the quantum dots comprise 0.5 to 10% by weight of the quantum dot ink.
The quantum dot ink according to claim 1, wherein said quantum dot ink has a boiling point in the range of 50 ° C to 300 ° C.
The quantum dot ink according to claim 5, wherein the quantum dot ink has a boiling point in the range of 120 ° C to 200 ° C.
The quantum dot ink of claim 1 wherein said quantum dot ink has a viscosity in the range of from 0.5 cPs to 40 cPs.
The quantum dot ink according to claim 7, wherein the quantum dot ink has a viscosity in the range of 2.0 cPs to 20 cPs.
The quantum dot ink according to claim 1, wherein said quantum dot ink has a surface tension in the range of 20 to 50 mN/m.
The quantum dot ink according to claim 9, wherein the quantum dot ink has a surface tension in the range of 25 to 35 mN/m.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dot structural unit is a graded alloy composition having a wider outer-level width in a radial direction, and is radially The energy levels of adjacent quantum dot structural units in the direction are continuous.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dot comprises at least three quantum dot structural units arranged in a radial direction, wherein the at least three quantum In the dot structure unit, the quantum dot structural unit located at the center and the surface is a graded alloy composition structure in which the width of the outer level is wider in the radial direction, and the quantum structure of the graded alloy component adjacent in the radial direction is quantum. The energy level of the point structural unit is continuous; a quantum dot structural unit between the central and surface quantum dot structural units is a homogeneous composition structure.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dots comprise two types of quantum dot structural units, wherein one type of quantum dot structural unit is radially outward The gradient alloy composition structure having a wider energy level width, and another type of quantum dot structural unit is a graded alloy composition structure in which the width of the outer energy level is narrower in the radial direction, the two types of quantum dot structural units The elements are alternately arranged in the radial direction, and the energy levels of the adjacent quantum dot structural units in the radial direction are continuous.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dot structural unit is a graded alloy composition having a wider outer-level width in a radial direction, and adjacent The energy levels of quantum dot structural units are discontinuous.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dot structural unit is a graded alloy composition having a narrower outer-level width in a radial direction, and adjacent The energy levels of quantum dot structural units are discontinuous.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dot comprises two kinds of quantum dot structural units, wherein one quantum dot structural unit has a larger outer-level width in a radial direction a wide graded alloy composition structure, another quantum dot structural unit is a uniform composition structure, the interior of the quantum dot includes one or more quantum dot structural units of a graded alloy composition structure, and is in a radial direction Quantum dot structure of adjacent graded alloy composition The energy levels of the cells are continuous; the exterior of the quantum dots includes one or more quantum dot structural units of a uniform composition structure.
The quantum dot ink according to any one of claims 1 to 10, wherein the quantum dot comprises two quantum dot structural units, wherein one quantum dot structural unit is a uniform composition structure, and another 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 inside of the quantum dot includes one or more quantum dot structural units of a uniform composition structure, and the outer portion of the quantum dot 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 quantum dot ink according to claim 1, wherein the quantum dot structural unit is a graded alloy component structure or a uniform alloy component structure comprising Group II and Group VI elements.
The quantum dot ink according to claim 1, wherein each of the quantum dot structural units comprises 2-20 layers of a single atomic layer, or each of the quantum dot structural units comprises 1 to 10 layers of unit cells. Floor.
The quantum dot ink according to claim 1, wherein the quantum dots have an emission peak wavelength ranging from 400 nm to 700 nm.
The quantum dot ink according to claim 1, wherein a half peak width of the luminescence peak of the quantum dot is from 12 nm to 80 nm.
A method for preparing a quantum dot ink according to any one of claims 1 to 21, comprising the steps of: first dispersing quantum dots in a solvent according to the above formula, and then stirring for 20 to 40 minutes to obtain a quantum dot ink. Wherein the solvent comprises at least one organic solvent.
The method for preparing a quantum dot ink according to claim 22, wherein the method for preparing the quantum dots 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 quantum dots, and the luminescence peak wavelength of the quantum dots exhibits one or more of blue shift, red shift, and constant.