CN108269892B

CN108269892B - Alloy material with quantum well energy level structure, preparation method and semiconductor device

Info

Publication number: CN108269892B
Application number: CN201611259516.3A
Authority: CN
Inventors: 杨一行; 刘政; 钱磊; 程陆玲
Original assignee: TCL Technology Group Co Ltd
Current assignee: TCL Technology Group Co Ltd
Priority date: 2016-12-30
Filing date: 2016-12-30
Publication date: 2021-06-22
Anticipated expiration: 2036-12-30
Also published as: CN108269892A

Abstract

The invention discloses an alloy material with a quantum well energy level structure, a preparation method and a QLED (quantum light emitting diode), wherein the alloy material comprises N structural units which are sequentially arranged in the radial direction, wherein N is more than or equal to 1; the structural unit is a gradually-changed alloy component structure with wider energy level width towards the outside in the radial direction; the energy level widths of adjacent building blocks are discontinuous. The invention provides a novel alloy material with abrupt alloy components along the radial direction from inside to outside, which not only realizes more efficient luminous efficiency, but also can meet the comprehensive performance requirements of a QLED device and a corresponding display technology on the alloy material, and is an ideal alloy material suitable for the QLED device and the display technology.

Description

Alloy material with quantum well energy level structure, preparation method and semiconductor device

Technical Field

The invention relates to the field of quantum dots, in particular to an alloy material with a quantum well energy level structure, a preparation method and a semiconductor device.

Background

The quantum dot is a special material which is limited to the nanometer order of magnitude in three dimensions, and the remarkable quantum confinement effect enables the quantum dot to have a plurality of unique nanometer properties: the emission wavelength is continuously adjustable, the light-emitting wavelength is narrow, the absorption spectrum is wide, the light-emitting intensity is high, the fluorescence lifetime is long, the biocompatibility is good, and the like. The characteristics enable the quantum dots to have wide application prospects in the fields of flat panel display, solid-state illumination, photovoltaic solar energy, biological markers and the like. Especially in the application of flat panel display, Quantum dot light-emitting diode (QLED) devices based on Quantum dot materials have shown great potential in the aspects of display image quality, device performance, manufacturing cost, etc. by virtue of the characteristics and optimization of Quantum dot nanomaterials. Although the performance of the QLED device in various aspects is improved in recent years, the gap between the basic device performance parameters such as device efficiency and device operation stability is still comparable to the requirement of industrial application, which also greatly hinders the development and application of the quantum dot electroluminescent display technology. In addition, not only the QLED device, but also in other fields, the characteristics of the quantum dot material relative to the conventional materials are being emphasized, for example, a photoluminescent device, a solar cell, a display device, a photodetector, a biological probe, a nonlinear optical device, and the like, and the following description will be given only by taking the QLED device as an example.

Although quantum dots have been researched and developed as a classical nanomaterial for more than 30 years, research time for utilizing the excellent light emitting characteristics of quantum dots and applying the quantum dots as a light emitting material in QLED devices and corresponding display technologies is still short; therefore, at present, most of the developments and researches of the QLED devices are based on the quantum dot materials of the existing classical structural systems, and the screening and optimization criteria of the corresponding quantum dot materials are still basically based on the self-luminescence properties of the quantum dots, such as the luminescence peak width of the quantum dots, the solution quantum yield and the like. The quantum dots are directly applied to the QLED device structure so as to obtain corresponding device performance results.

However, as a set of complex optoelectronic device systems, the QLED device and the corresponding display technology have many factors that affect the performance of the device. Starting with quantum dot materials as core light-emitting layer materials alone, the quantum dot performance index required for balancing is much more complex.

Firstly, quantum dots exist in a form of a solid film of a quantum dot light emitting layer in a QLED device, so that various luminescent performance parameters originally obtained in a solution of a quantum dot material show obvious differences after the solid film is formed: for example, the emission peak wavelength in the solid thin film is red-shifted (shifted to a long wavelength), the emission peak width is increased, and the quantum yield is reduced to various degrees, that is, the excellent emission performance of the quantum dot material in the solution cannot be completely inherited to the quantum dot solid thin film of the QLED device. Therefore, when the structure and the synthesis formula of the quantum dot material are designed and optimized, the optimization of the luminous performance of the quantum dot material and the inheritance maximization of the luminous performance of the quantum dot material in a solid thin film state need to be considered at the same time.

And secondly, the light emission of the quantum dot material in the QLED device is realized by electric excitation, namely holes and electrons are respectively injected from the anode and the cathode of the QLED device through electrification, and the holes and the electrons are transmitted through corresponding functional layers in the QLED device and are recombined in a quantum dot light-emitting layer, and then photons are emitted in a radiation transition mode, so that the light emission is realized. From the above process, it can be seen that the light emitting performance of the quantum dot itself, such as the light emitting efficiency, only affects the efficiency of the radiative transition in the above process, and the overall light emitting efficiency of the QLED device is also affected by the charge injection and transport efficiency of the holes and electrons in the quantum dot material, the relative charge balance of the holes and electrons in the quantum dot material, the recombination region of the holes and electrons in the quantum dot material, and the like. Therefore, when designing and optimizing the structure of the quantum dot material, especially the fine core-shell nanostructure of the quantum dot, the electrical properties of the quantum dot after forming the solid film need to be considered in an important way: such as charge injection and conduction properties of the quantum dots, fine band structure of the quantum dots, exciton lifetime of the quantum dots, and the like.

Finally, considering that QLED devices and corresponding display technologies will not be prepared by solution methods, such as inkjet printing, which have great production cost advantages in the future, material design and development of quantum dots requires consideration of the processability of quantum dot solutions, such as the dispersibility and solubility of quantum dot solutions or printing inks, colloidal stability, print film forming properties, and the like. Meanwhile, the development of quantum dot materials is coordinated with other functional layer materials of the QLED device and the overall preparation process flow and requirements of the device.

In a word, the conventional quantum dot structure design only considering the improvement of the self-luminous performance of the quantum dot cannot meet the comprehensive requirements of the QLED device and the corresponding display technology on the quantum dot material in various aspects such as optical performance, electrical performance, processing performance and the like. The fine core-shell structure, components, energy level and the like of the quantum dot luminescent material need to be customized according to the requirements of the QLED device and the corresponding display technology.

Due to the high surface atomic ratio of the quantum dots, atoms that do not form non-covalent bonds (Dangling bonds) with surface ligands (Ligand) will exist in a surface defect state that will cause transitions in non-radiative pathways such that the luminescent quantum yield of the quantum dots is greatly reduced. In order to solve the problem, a semiconductor shell layer containing another semiconductor material can be grown on the surface of the outer layer of the original quantum dot to form a core-shell structure of the quantum dot, so that the luminous performance of the quantum dot can be obviously improved, and the stability of the quantum dot is improved.

The quantum dot material applicable to the development of the high-performance QLED device is mainly a quantum dot with a core-shell structure, wherein the core and the shell components are respectively fixed, and the core-shell structure has a definite boundary, such as the quantum dot with a CdSe/ZnS core-shell structure (J. Phys. chem., 1996, 100 (2), 468-. In these quantum dots of the core-shell structure, generally speaking, the composition components of the core and the shell are fixed and different, and are generally a binary compound system composed of one kind of cation and one kind of anion. In this structure, since the growth of the core and the shell is independently and separately performed, the boundary between the core and the shell is definite, i.e., the core and the shell can be distinguished. The development of the core-shell structure quantum dot improves the luminous quantum efficiency, monodispersity and quantum dot stability of the original single-component quantum dot.

Although the quantum dot performance of the quantum dot with the core-shell structure is partially improved, the luminescent performance is still to be improved from the design idea and the optimization scheme or based on the aspect of improving the luminous efficiency of the quantum dot, and in addition, the special requirements of the semiconductor device on other aspects of the quantum dot material are not comprehensively considered.

Therefore, the above-described technology is yet to be improved and developed.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide an alloy material having a quantum well energy level structure, a preparation method thereof and a semiconductor device, and aims to solve the problems that the luminescent performance of the conventional quantum dot material needs to be improved and the requirements of the semiconductor device on the quantum dot material cannot be met.

The technical scheme of the invention is as follows:

the alloy material with the quantum well energy level structure comprises N structural units which are sequentially arranged in the radial direction, wherein N is more than or equal to 1;

the structural unit is a gradually-changed alloy component structure with wider energy level width towards the outside in the radial direction;

the energy levels of adjacent building blocks are discontinuous.

The alloy material is characterized in that the energy level width of a structural unit close to the center of the alloy material is smaller than the energy level width of a structural unit far away from the center of the alloy material.

The alloy material is characterized in that the structural unit is a graded alloy component structure containing II-group and VI-group elements.

The alloy material is characterized in that the alloy component of the structural unit is Cd_xZn_1-xSe_yS_1-yWherein x is not less than 0 and not more than 1, y is not less than 0 and not more than 1, and x and y are not 0 and not 1 at the same time.

The alloy material is characterized in that in the structural unit, the alloy component at the point A is Cd_x ^AZn_1-x ^ASe_y ^AS_1-y ^AThe alloy component at the B point is Cd_x ^BZn_1-x ^BSe_y ^BS_1-y ^BWherein the point A is closer to the center of the alloy material than the point B, and the compositions of the point A and the point B meet the following conditions:_x ^A＞_x ^B，_y ^A＞_y ^B。

the alloy material, wherein the structural unit comprises 2 to 20 monoatomic layers, or the structural unit comprises 1 to 10 unit cell layers.

The alloy material is characterized in that an abrupt structure is formed between two monoatomic layers at the junction of the adjacent structural units in the radial direction, or an abrupt structure is formed between two unit cell layers at the junction of the adjacent structural units in the radial direction.

The alloy material is characterized in that the wavelength range of the light emission peak of the alloy material is 400-700 nm.

The alloy material is characterized in that the half-height peak width of a luminous peak of the alloy material is 12-80 nanometers.

A method for preparing the alloy material, which comprises the following steps:

synthesizing a first compound at a predetermined position;

synthesizing a second compound on the surface of a first compound, wherein the alloy components of the first compound and the second compound are the same or different;

and (3) enabling the first compound and the second compound to perform cation exchange reaction to form an alloy material, wherein the wavelength of the luminous peak of the alloy material is subjected to discontinuous blue shift.

The preparation method of the alloy material comprises the step of preparing a first compound and/or a second compound, wherein the cation precursor of the first compound and/or the second compound comprises a Zn precursor, and the Zn precursor is at least one of dimethyl zinc, diethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc oleate or zinc stearate.

The preparation method of the alloy material comprises the step of preparing a first compound and/or a second compound, wherein a cation precursor of the first compound and/or the second compound comprises a precursor of Cd, and the precursor of Cd is at least one of dimethyl cadmium, diethyl cadmium, cadmium acetate, cadmium acetylacetonate, cadmium iodide, cadmium bromide, cadmium chloride, cadmium fluoride, cadmium carbonate, cadmium nitrate, cadmium oxide, cadmium perchlorate, cadmium phosphate, cadmium sulfate, cadmium oleate or cadmium stearate.

The preparation method of the alloy material comprises the step of preparing the first compound and/or the second compound by using a precursor of Se, wherein the precursor of Se is at least one of Se-TOP, Se-TBP, Se-TPP, Se-ODE, Se-OA, Se-ODA, Se-TOA, Se-ODPA or Se-OLA.

The preparation method of the alloy material comprises the step of preparing the first compound and/or the second compound, wherein the anion precursor of the first compound and/or the second compound comprises a precursor of S, and the precursor of S is at least one of S-TOP, S-TBP, S-TPP, S-ODE, S-OA, S-ODA, S-TOA, S-ODPA, S-OLA or alkyl mercaptan.

The preparation method of the alloy material comprises the step of preparing the first compound and/or the second compound, wherein the anion precursor of the first compound and/or the second compound comprises a precursor of Te, and the precursor of Te is at least one of Te-TOP, Te-TBP, Te-TPP, Te-ODE, Te-OA, Te-ODA, Te-TOA, Te-ODPA or Te-OLA.

The method for producing the alloy material, wherein a cation exchange reaction occurs between the first compound and the second compound under heating.

The preparation method of the alloy material comprises the step of heating to 100-400 ℃.

The preparation method of the alloy material comprises the step of heating for 2 s-24 h.

The preparation method of the alloy material comprises the step of synthesizing the first compound, wherein the molar ratio of the cation precursor to the anion precursor is 100:1 to 1: 50.

The preparation method of the alloy material comprises the step of synthesizing the second compound, wherein the molar ratio of the cation precursor to the anion precursor is 100:1 to 1: 50.

A semiconductor device comprising an alloy material as claimed in any one of the preceding claims.

The semiconductor device is any one of an electroluminescent device, a photoluminescent device, a solar cell, a display device, a photoelectric detector, a biological probe and a nonlinear optical device.

Has the advantages that: the invention provides a novel alloy material with abrupt alloy components along the radial direction from inside to outside, which not only realizes more efficient luminous efficiency, but also can meet the comprehensive performance requirements of semiconductor devices and corresponding display technologies on quantum dot materials, and is an ideal quantum dot luminous material suitable for the semiconductor devices and the display technologies.

Drawings

FIG. 1 is a graph of the energy level structure of a preferred embodiment of the present invention alloy material with quantum well energy level structure.

Fig. 2 is a schematic structural diagram of a quantum dot light-emitting diode in embodiment 13 of the present invention.

Fig. 3 is a schematic structural diagram of a quantum dot light emitting diode in embodiment 14 of the present invention.

Fig. 4 is a schematic structural diagram of a quantum dot light-emitting diode in embodiment 15 of the present invention.

Fig. 5 is a schematic structural diagram of a quantum dot light emitting diode in embodiment 16 of the present invention.

Fig. 6 is a schematic structural diagram of a quantum dot light-emitting diode in embodiment 17 of the present invention.

Fig. 7 is a schematic structural diagram of a quantum dot light-emitting diode in embodiment 18 of the present invention.

Detailed Description

The present invention provides an alloy material having a quantum well energy level structure, a method for manufacturing the same, and a semiconductor device, and the present invention will be described in further detail below in order to make the objects, technical solutions, and effects of the present invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The alloy material of the quantum well energy level structure comprises N structural units which are sequentially arranged in the radial direction, wherein N is more than or equal to 1;

the energy levels of adjacent building blocks are discontinuous.

The energy level structure of the alloy material is shown in fig. 1, namely the alloy material is formed by sequentially arranging a plurality of structural units in a mutation mode, and the structural units are all gradient alloy component structures with wider energy level widths towards the outside in the radial direction. In the following embodiments, the energy level structure of such quantum dots is referred to as a quantum well energy level structure. The radial direction herein refers to a direction outward from the center of the alloy material, for example, if the alloy material of the present invention has a spherical or spherical-like structure, the radial direction refers to a direction along a radius, the center of the alloy material refers to the center of its physical structure, and the surface of the alloy material refers to the surface of its physical structure.

In the alloy material, the energy level widths of the adjacent structural units are discontinuous, namely the energy level widths of the adjacent structural units have the characteristic of discontinuous change, namely the energy level widths have the characteristic of mutation, namely the synthetic components of the alloy material also have the characteristic of mutation. In addition, the structural units may be arranged in sequence in unit groups, for example, from the center to the surface, the structural units in the first group, the structural units in the second group, the structural units in the third group … are in sequence, the number of the structural units in each group may be the same or different, and the energy levels of the adjacent structural units in each group are continuous, that is, the structure of the graded alloy composition is formed. However, the energy levels of the adjacent groups of structural units are not continuous, and thus, an abrupt structure is formed.

Further, in the alloy material, the energy level width of the structural unit near the center is smaller than the energy level width of the structural unit far from the center. That is, in the alloy material, the energy level width from the center to the surface is gradually widened, so as to form a funnel-type structure with a discontinuous opening gradually enlarged, where the gradual enlargement of the opening refers to a variation trend of the energy level width in a direction from the center of the alloy material to the surface of the alloy material in the energy level structure shown in fig. 1, and in the following embodiment, the energy level structure of the quantum dot is referred to as a quantum well energy level structure. Of course, the alloy material is not limited to the above manner, that is, the energy level width of the structural unit far from the center may be smaller than that of the structural unit near the center, and in this structure, the energy level widths of the adjacent structural units overlap with each other.

Specifically, the structural unit comprises group II and group VI elements, i.e., the structural unit is a graded alloy composition structure comprising group II and group VI elements. The group II elements include, but are not limited to, Zn, Cd, Hg, Cn, and the like. The group VI elements include, but are not limited to, O, S, Se, Te, Po, Lv, and the like.

The alloy component of the structural unit is Cd_xZn_1-xSe_yS_1-yWherein x is not less than 0 and not more than 1, y is not less than 0 and not more than 1, and x and y are not 0 and not 1 at the same time. For example, Cd as the alloy component at a certain point_0.5Zn_0.5Se_0.5S_0.5And the other alloy component is Cd_0.3Zn_0.7Se_0.4S_0.6。

In the structural unit, the alloy component of the point A is Cd_x ^AZn_1-x ^ASe_y ^AS_1-y ^AThe alloy component at the B point is Cd_x ^BZn_1- _x ^BSe_y ^BS_1-y ^BWherein the point A is closer to the center of the alloy material than the point B, and the compositions of the point A and the point B meet the following conditions:_x ^A＞_x ^B，_y ^A＞_y ^B. That is, for any two points in the structural unit, point A and point B, and point A is closer to the center of the alloy material than point B, then_x ^A＞_x ^B，_y ^A＞_y ^BThat is, the Cd content at the point A is greater than that at the point B, the Zn content at the point A is less than that at the point B, and the Se content at the point A is largeThe Se content at the B site is smaller than the S content at the A site. Thus, in the structural unit, a graded structure is formed in the radial direction, and since the Cd and Se contents are lower and the Zn and S contents are higher the further outward (i.e., away from the center of the alloy material) in the radial direction, the energy level width thereof will be wider according to the characteristics of these elements.

The structural unit comprises 2-20 monoatomic layers. I.e. each building block comprises 2-20 monoatomic layers. Preferably 2 monoatomic layers to 5 monoatomic layers, and the preferred number of layers can ensure that the quantum dots realize good luminous quantum yield and high charge injection efficiency.

Further, each monoatomic layer is a minimum structural unit, that is, the alloy components of the monoatomic layer of each layer are fixed.

Preferably, an abrupt structure is formed between two monoatomic layers interfacing adjacent structural units in the radial direction, i.e. an abrupt alloy composition structure is formed, i.e. the energy level widths of the two monoatomic layers at the interface of the two structural units are not continuous, but abrupt, so that the energy level profile of the entire alloy material forms an intermittent profile.

Alternatively, each structural unit comprises 1-10 layers of unit cells, for example 2-5 layers of unit cells. The unit cell layers are the smallest structural units, i.e., the alloy composition of the unit cell layers of each layer is fixed, i.e., each unit cell layer has the same lattice parameter and elements. Each structural unit is a closed unit cell curved surface formed by connecting unit cell layers, but an abrupt structure is formed between two unit cell layers at the boundary of the adjacent structural units in the radial direction, namely an abrupt alloy component structure is formed, namely, the energy levels of the two unit cell layers at the boundary of the two structural units are not continuous but abrupt, so that the energy level curve of the whole alloy material forms an intermittent curve.

That is, the alloy material of the present invention is an alloy composition structure having a discontinuity in the radial direction from the inside to the outside. The quantum dot structure has the characteristic of discontinuous change along the radial direction from inside to outside in the composition; correspondingly, the energy level distribution also has the characteristic of discontinuous change along the radial direction from inside to outside; compared with the relation between quantum dot core and shell with definite boundary, the alloy material of the invention is not only beneficial to realizing more efficient luminous efficiency, but also can meet the comprehensive performance requirement of QLED devices and corresponding display technologies on alloy materials, and is an ideal quantum dot luminous material suitable for QLED devices and display technologies.

The invention adopts the alloy material with the structure, the luminous quantum yield range can be realized to be 1-100%, the preferred luminous quantum yield range is 30-100%, and the preferred luminous quantum yield range can ensure the good applicability of the quantum dots.

By adopting the alloy material with the structure, the luminous peak wavelength range can be 400-700 nm, the preferable luminous peak wavelength range is 430-660 nm, and the preferable quantum dot luminous peak wavelength range can ensure that the luminous quantum yield of the alloy material is more than 30% in the range.

In the invention, the half-height peak width of the luminous peak of the alloy material is 12 to 80 nanometers.

The alloy material provided by the invention has the following beneficial effects: firstly, the method is beneficial to reducing the lattice tension among quantum dot crystals with different alloy components to the maximum extent and relieving the lattice mismatch, thereby reducing the formation of interface defects and improving the luminous efficiency of the quantum dots. Secondly, the energy level structure formed by the alloy material provided by the invention is more beneficial to effectively constraining the electron cloud in the quantum dot, and greatly reduces the diffusion probability of the electron cloud to the surface of the quantum dot, thereby greatly inhibiting the Auger recombination loss of the non-radiative transition of the quantum dot, reducing the scintillation of the quantum dot and improving the light efficiency of the quantum dot. Thirdly, the energy level structure formed by the alloy material provided by the invention is more beneficial to improving the injection efficiency and the transmission efficiency of the charge of the quantum dot light emitting layer in the QLED device; meanwhile, the accumulation of charges and the quenching of excitons generated by the accumulation can be effectively avoided. Fourthly, the easily-controlled diversified performance level structures formed by the alloy material provided by the invention can fully meet and match with the energy level structures of other functional layers in the device to realize the matching of the whole energy level structures of the device, thereby being beneficial to realizing the high-efficiency QLED device.

The invention also provides a preparation method of the alloy material, which comprises the following steps:

synthesizing a first compound at a predetermined position;

The preparation method combines a quantum dot SILAR synthesis method with a quantum dot one-step synthesis method to generate the alloy material, and specifically utilizes the quantum dot layer-by-layer growth and the quantum dot one-step synthesis method to form the transition shell with the gradually-changed components. That is, two compound thin layers having the same or different alloy compositions are sequentially formed at predetermined positions, and a gradual composition distribution at the predetermined positions is achieved by causing a cation exchange reaction between the two compounds. The gradual change component distribution at the preset position in the radial direction can be continuously realized by repeating the above processes, and the abrupt alloy component distribution on the whole quantum dot is realized due to the discontinuous blue shift in the repeating process.

The first compound and the second compound can be binary or more compounds.

The alloy material has discontinuous blue shift in the wavelength of the light emission peak. The occurrence of blue shift represents that the luminescence peak is shifted to the short wave direction and the energy level width is widened. Of course, the red shift of the emission peak wavelength means that the emission peak shifts in the long-wavelength direction and the energy level width becomes narrower, while the unchanged emission peak wavelength means that the energy level width does not change. In the present invention, the occurrence of discontinuous blue shift means that the energy level width between the structural units is changed abruptly rather than continuously.

The cationic precursor of the first compound and/or the second compound comprises: a precursor of Zn, which is at least one of dimethyl Zinc (dimethyl Zinc), diethyl Zinc (diethyl Zinc), Zinc acetate (Zinc acetate), Zinc acetylacetonate (Zinc acetate), Zinc iodide (Zinc iodide), Zinc bromide (Zinc bromide), Zinc chloride (Zinc chloride), Zinc fluoride (Zinc fluoride), Zinc carbonate (Zinc carbonate), Zinc cyanide (Zinc cyanide), Zinc nitrate (Zinc nitrate), Zinc oxide (Zinc oxide), Zinc peroxide (Zinc peroxide), Zinc perchlorate (Zinc perchlorate), Zinc sulfate (Zinc sulfate), Zinc oleate (Zinc oleate), or Zinc stearate (Zinc stearate), 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 Cd is at least one of cadmium dimethyl (dimethyl) chloride, cadmium diethyl (diethyl) chloride, cadmium acetate (cadmium acetate), cadmium acetylacetonate (cadmium acetate), cadmium iodide (cadmium iodide), cadmium bromide (cadmium bromide), cadmium chloride (cadmium chloride), cadmium fluoride (cadmium fluoride), cadmium carbonate (cadmium carbonate), cadmium nitrate (cadmium nitrate), cadmium oxide (cadmium oxide), cadmium perchlorate (cadmium perchlorate), cadmium phosphate (cadmium phosphate), cadmium sulfate (cadmium sulfate), cadmium oleate (cadmium oleate), or cadmium stearate (cadmium stearate), but is not limited thereto.

The first compound and/or the second compound includes a precursor of Se, for example, a compound formed by any combination of Se and some organic substances, and may be at least one of Se-TOP (selenium-triarylphosphine), Se-TBP (selenium-tributylphosphine), Se-TPP (selenium-triphenylphosphine), Se-ODE (selenium-1-octadiene), Se-OA (selenium-oleic acid), Se-ODA (selenium-octadiene), Se-TOA (selenium-octadiene), Se-olpa (selenium-octadiene acid), 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, for example, a compound formed by any combination of S and some organic substances, and specifically, may be S-TOP (sulfur-trioctylphosphine), S-TBP (sulfur-tributyphosphine), S-TPP (sulfur-triphenylphosphine), S-ODE (sulfur-1-octacene), S-OA (sulfur-oleic acid), S-ODA (sulfur-octacylimine), S-TOA (sulfur-trioctylamine), S-ODPA (sulfur-octacylphosphonic acid) or S-OLA (sulfur-olyvinylamine), etc., but is not limited thereto; the precursor of S may also be alkyl thiol (alkyl thiol), which may be at least one of hexanethiol (hexanethiol), octanethiol (octanethiol), decanethiol (decanethiol), dodecanethiol (docetaethiol), hexadecanethiol (hexanetaethiol) or mercaptopropylsilane (mercaptopropylalane), etc., but is not limited thereto.

The anion precursor of the first compound and/or the second compound comprises a precursor of Te, and the precursor of Te is at least one of Te-TOP, Te-TBP, Te-TPP, Te-ODE, Te-OA, Te-ODA, Te-TOA, Te-ODPA or Te-OLA.

The cation precursor and the anion precursor can be selected according to the composition of the final alloy material, and one or more of the cation precursor and the anion precursor can be selected according to the following conditions: for example, synthesis of Cd_xZn_1-xSe_yS_1-yThe alloy material of (1) needs a precursor of Cd, a precursor of Zn, a precursor of Se and a precursor of S; synthesis of Cd if required_xZn_1-xWhen the alloy material of S is adopted, a precursor of Cd, a precursor of Zn and a precursor of S are needed; synthesis of Cd if required_xZn_1-xIn the case of an alloy material of Se, a precursor of Cd, a precursor of Zn, and a precursor of Se are required.

In the production method of the present invention, the cation exchange reaction is preferably carried out under conditions such that the heating reaction is carried out, for example, at a temperature of from 100 ℃ to 400 ℃, preferably at a temperature of from 150 ℃ to 380 ℃. The heating time is between 2s and 24h, and the preferable heating time is between 5min and 4 h.

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

The molar ratio of the cationic precursor to the anionic precursor in forming each layer of the compound is from 100:1 to 1:50 (specifically, the molar charge ratio of the cation to the anion), for example, the molar ratio of the cationic precursor to the anionic precursor in forming the first layer of the compound is from 100:1 to 1: 50; in forming the second layer of compounds, the molar ratio of the cationic precursor to the anionic precursor is from 100:1 to 1:50, preferably from 20:1 to 1:10, the preferred molar ratio of the cationic precursor to the anionic precursor being such as to ensure a reaction rate in the easily controllable range.

The alloy material prepared by the preparation method has the luminescence peak wavelength range of 400-700 nm, the preferred luminescence peak wavelength range of 430-660 nm, and the preferred quantum dot luminescence peak wavelength range can ensure that the quantum dot can realize the luminescence quantum yield of more than 30% in the range.

The alloy material prepared by the preparation method has the luminescence quantum yield range of 1-100%, the preferred luminescence quantum yield range of 30-100%, and the preferred luminescence quantum yield range can ensure the good applicability of the quantum dots.

In addition to the preparation of the alloy material of the present invention according to the above preparation method, the present invention provides another preparation method of the alloy material as described above, which comprises the steps of:

adding one or more than one cation precursor at a preset position in the radial direction; and simultaneously adding one or more than one anion precursor, so that the cation precursor and the anion precursor react to form the alloy material, and the wavelength of the luminous peak of the alloy material generates discontinuous blue shift in the reaction process.

The difference between this method and the former method is that the former method forms two layers of compounds in sequence, then the cation exchange reaction occurs, thereby realizing the component distribution of the alloy material of the invention, while the latter method is that the cation precursor and the anion precursor of the alloy component required to be synthesized are directly controlled to be added at the preset position, and the reaction is carried out to form the alloy material, thereby realizing the alloy component distribution required by the invention. In the latter method, the reaction principle is that the cation precursor and the anion precursor with high reactivity react first, the cation precursor and the anion precursor with low reactivity react later, and different cations undergo cation exchange reaction in the reaction process, so that the distribution of the alloy components required by the invention is realized. The kinds of the cationic precursor and the anionic precursor have been described in detail in the foregoing method. The reaction temperature, reaction time, and mixture ratio may be varied according to the specific alloy materials to be synthesized, and are substantially the same as the former method, and will be described with reference to the following examples.

The invention also provides a semiconductor device comprising the alloy material as described in any one of the above.

Taking an electroluminescent device as an example, the invention provides a quantum dot electroluminescent device QLED taking the alloy material as a luminescent layer material. The quantum dot electroluminescent device can realize that: 1) high efficiency charge injection, 2) high luminance, 3) low driving voltage, 4) high device efficiency, and the like. Meanwhile, the alloy material has the characteristics of easy control and various performance level structures, and can fully meet and match with the energy level structures of other functional layers in the device to realize the matching of the integral energy level structure of the device, thereby being beneficial to realizing the high-efficiency and stable QLED device.

The photoluminescence device refers to a device which obtains energy by depending on an external light source for irradiation, generates excitation to cause luminescence, and can cause photoluminescence such as phosphorescence and fluorescence by ultraviolet radiation, visible light and infrared radiation. The alloy material can be used as a luminescent material of a photoluminescence device.

The solar cell is also called a photovoltaic device, and the alloy material can be used as a light absorption material of the solar cell, so that various performances of the photovoltaic device are effectively improved.

The display device refers to a backlight module or a display panel using the backlight module, and the display panel can be applied to various products, such as a display, a tablet computer, a mobile phone, a notebook computer, a flat-panel television, a wearable display device or other products including display panels with different sizes.

The photoelectric detector is a device capable of converting an optical signal into an electric signal, and the principle is that the conductivity of an irradiated material is changed due to radiation, and the quantum dot material is applied to the photoelectric detector, so that the photoelectric detector has the following advantages: the optical fiber is sensitive to vertical incident light, has high photoconductive responsivity, high specific detectivity and continuously adjustable detection wavelength, and can be prepared at low temperature. In the operation process of the photoelectric detector with the structure, the photo-generated electron-hole pairs generated after the quantum dot photosensitive layer (namely the alloy material disclosed by the invention) absorbs photons can be separated under the action of a built-in electric field, so that the photoelectric detector with the structure has lower driving voltage, can work under low external bias voltage even 0 external bias voltage, and is easy to control.

The biological probe is a device which modifies a certain material to have a labeling function, for example, the alloy material is coated to form a fluorescent probe, and the fluorescent probe is applied to the field of cell imaging or substance detection.

The nonlinear optical device belongs to the technical field of optical laser, and is widely applied, such as electro-optical switching and laser modulation, laser frequency conversion and laser frequency tuning; optical information processing is carried out, and imaging quality and light beam quality are improved; as nonlinear etalons and bistable devices; the high excited state and high resolution spectrum of the substance and the transfer process of the internal energy and excitation of the substance and other relaxation processes are researched.

Example 1: preparation of quantum dots based on CdZnSeS/CdZnSeS

Firstly, injecting a precursor of cation Cd, a precursor of cation Zn, a precursor of anion Se and a precursor of anion S into a reaction system to form Cd_yZn_1-ySe_bS_1-bA layer (wherein y is 0. ltoreq. y.ltoreq.1, b is 0. ltoreq. b.ltoreq.1); continuously injecting a precursor of cation Cd, a precursor of cation Zn, a precursor of anion Se and a precursor of anion S into a reaction system, wherein Cd is in a structure shown in the specification_yZn_1-ySe_bS_1-bCd formed on the surface of the layer_zZn_1-zSe_cS_1-cA layer (where 0. ltoreq. z.ltoreq.1, and z is not equal to y, 0. ltoreq. c.ltoreq.1); under the reaction conditions of certain heating temperature, heating time and the like, the exchange of Cd and Zn ions in the inner and outer layer nanocrystals (namely the two-layer compound) occurs; cd is the difference between the number of cations that migrate from a first to a second_yZn_1-ySe_bS_1-bLayer and Cd_zZn_1-zSe_cS_1-cA graded alloy composition distribution of Cd content and Zn content is formed near the interface of the layers, i.e. Cd_xZn_1-xSe_aS_1-aWherein x is more than or equal to 0 and less than or equal to 1, and a is more than or equal to 0 and less than or equal to 1.

Example 2: preparation method of quantum dots based on CdZnS/CdZnS

Firstly, injecting a precursor of cation Cd, a precursor of cation Zn and a precursor of anion S into a reaction system to form Cd_yZn_1-yAn S layer (wherein y is more than or equal to 0 and less than or equal to 1); continuously injecting a precursor of cation Cd, a precursor of cation Zn and a precursor of anion S into the reaction systemIn the above Cd_yZn_1-yCd formed on the surface of the S layer_zZn_1-zAn S layer (wherein z is more than or equal to 0 and less than or equal to 1, and z is not equal to y); under the reaction conditions of certain heating temperature, heating time and the like, the exchange of Cd and Zn ions in the inner and outer layer nanocrystals (namely the two-layer compound) occurs; cd is the difference between the number of cations that migrate from a first to a second_yZn_1-yS layer and Cd_zZn_1-zThe interface of the S layer is formed with a gradual alloy component distribution of Cd content and Zn content, namely Cd_xZn_1-xAnd S, wherein x is more than or equal to 0 and less than or equal to 1.

Example 3: preparation of quantum dots based on CdZnSe/CdZnSe

Firstly, injecting a precursor of cation Cd, a precursor of cation Zn and a precursor of anion Se into a reaction system to form Cd_yZn_1-yA Se layer (wherein y is more than or equal to 0 and less than or equal to 1); continuously injecting a precursor of cation Cd, a precursor of cation Zn and a precursor of anion Se into a reaction system to react with the Cd_yZn_1-yForming Cd on the surface of the Se layer_zZn_1-zA Se layer (wherein z is 0-1 and z is not equal to y); under the reaction conditions of certain heating temperature, heating time and the like, the exchange of Cd and Zn ions in the inner and outer layer nanocrystals occurs; cd is the difference between the number of cations that migrate from a first to a second_yZn_1-ySe layer and Cd_zZn_1-zThe gradual alloy component distribution of Cd content and Zn content is formed near the interface of the Se layer, namely Cd_xZn_1-xSe, wherein x is more than or equal to 0 and less than or equal to 1.

Example 4: preparation based on CdS/ZnS quantum dots

Injecting a precursor of cation Cd and a precursor of anion S into a reaction system to form a CdS layer; continuously injecting a precursor of cation Zn and a precursor of anion S into the reaction system, and forming a ZnS layer on the surface of the CdS layer; under the reaction conditions of certain heating temperature, heating time and the like, Zn cations on the outer layer gradually migrate to the inner layer and undergo cation exchange reaction with Cd cations, namely Cd ionsThe seed migrates to the outer layer, and exchange of Cd and Zn ions occurs; since the migration distance of the cations is limited and the probability of migration is smaller when the migration distance is farther away, a graded alloy composition distribution in which the Cd content gradually decreases along the radial direction outwards and the Zn content gradually increases along the radial direction outwards, namely Cd is formed near the interface of the CdS layer and the ZnS layer_xZn_1-xS, wherein x is more than or equal to 0 and less than or equal to 1, and x is monotonically decreased from 1 to 0 from inside to outside (in the radial direction).

Example 5: preparation based on CdSe/ZnSe quantum dots

Injecting a precursor of cation Cd and a precursor of anion Se into a reaction system to form a CdSe layer; continuously injecting a precursor of cation Zn and a precursor of anion Se into the reaction system to form a ZnSe layer on the surface of the CdSe layer; under the reaction conditions of certain heating temperature, heating time and the like, Zn cations on the outer layer gradually migrate to the inner layer and undergo cation exchange reaction with Cd cations, namely Cd ions migrate to the outer layer and exchange between Cd and Zn ions; because the migration distance of the cations is limited and the probability of migration is smaller when the migration distance is farther away, a gradient alloy component distribution that the content of Cd gradually decreases along the radial direction outwards and the content of Zn gradually increases along the radial direction outwards is formed near the interface of the CdSe layer and the ZnSe layer, namely Cd_xZn_1-xSe, wherein x is more than or equal to 0 and less than or equal to 1, and x monotonically decreases from 1 to 0 from inside to outside (radial direction).

Example 6: preparation based on CdSeS/ZnSeS quantum dots

Firstly, injecting a precursor of cation Cd, a precursor of anion Se and a precursor of anion S into a reaction system to form CdSe_bS_1-bA layer (wherein 0. ltoreq. b. ltoreq.1); the CdSe precursor, the anion Se precursor and the anion S precursor are injected into the reaction system_bS_1-bZnSe formed on the surface of the layer_cS_1-cA layer (wherein 0. ltoreq. c. ltoreq.1); under the reaction conditions of certain heating temperature, heating time and the like, Zn cations on the outer layer gradually migrate to the inner layer and undergo cation exchange reaction with Cd cations, namely Cd ions migrate to the outer layer and take placeExchanging Cd and Zn ions; CdSe is a common phenomenon because the migration distance of cations is limited and the probability of migration is smaller for longer migration distances_bS_1-bLayer and ZnSe_cS_1-cA gradient alloy component distribution that the Cd content gradually decreases along the radial direction and the Zn content gradually increases along the radial direction is formed near the interface of the layers, namely Cd_xZn_1-xSe_aS_1-aWherein x is more than or equal to 0 and less than or equal to 1, x is monotonically decreased from 1 to 0 from inside to outside (in the radial direction), and a is more than or equal to 0 and less than or equal to 1.

Example 7: preparation based on ZnS/CdS quantum dots

Injecting a precursor of cation Zn and a precursor of anion S into a reaction system to form a ZnS layer; continuously injecting a precursor of the cation Cd and a precursor of the anion S into the reaction system, and forming a CdS layer on the surface of the ZnS layer; under the reaction conditions of certain heating temperature, heating time and the like, Cd cations on the outer layer gradually migrate to the inner layer and undergo cation exchange reaction with Zn cations, namely Zn ions migrate to the outer layer and exchange Cd and Zn ions; since the migration distance of the cations is limited and the probability of migration is smaller for the farther migration distance, a graded alloy composition distribution, i.e., a distribution of Cd in which the Zn content gradually decreases and the Cd content gradually increases radially outward, is formed near the interface between the ZnS layer and the CdS layer_xZn_1-xS, wherein x is more than or equal to 0 and less than or equal to 1, and x is monotonically increased from 0 to 1 from inside to outside (radial direction).

Example 8: preparation based on ZnSe/CdSe quantum dots

Firstly, injecting a precursor of cation Zn and a precursor of anion Se into a reaction system to form a ZnSe layer; continuously injecting a precursor of the cation Cd and a precursor of the anion Se into the reaction system to form a CdSe layer on the surface of the ZnSe layer; under the reaction conditions of certain heating temperature, heating time and the like, Cd cations on the outer layer gradually migrate to the inner layer and undergo cation exchange reaction with Zn cations, namely Zn ions migrate to the outer layer and exchange Cd and Zn ions; since the migration distance of cations is limited and the probability of migration occurring at a longer migration distance is smaller, theWill form a gradual alloy component distribution with Zn content gradually reduced along the radial direction and Cd content gradually increased along the radial direction near the interface of the ZnSe layer and the CdSe layer, namely Cd_xZn_1-xSe, where x is 0. ltoreq. x.ltoreq.1 and x monotonically increases from 0 to 1 from the inside to the outside (radial direction).

Example 9: preparation of ZnSeS/CdSeS-based quantum dots

Firstly, injecting a precursor of cation Zn, a precursor of anion Se and a precursor of anion S into a reaction system to form ZnSe_bS_1-bA layer (wherein 0. ltoreq. b. ltoreq.1); continuously injecting the precursor of the cation Cd, the precursor of the anion Se and the precursor of the anion S into the reaction system to form the CdSe on the surface of the ZnSebS1-b layer_cS_1-cA layer (wherein 0. ltoreq. c. ltoreq.1); under the reaction conditions of certain heating temperature, heating time and the like, Cd cations on the outer layer gradually migrate to the inner layer and undergo cation exchange reaction with Zn cations, namely Zn ions migrate to the outer layer and exchange Cd and Zn ions; since the migration distance of cations is limited and the probability of migration occurring at a longer migration distance is smaller, it is in ZnSe_bS_1-bLayer with CdSe_cS_1-cA gradient alloy component distribution that the Zn content gradually decreases along the radial direction and the Cd content gradually increases along the radial direction is formed near the interface of the layers, namely Cd_xZn_1-xSe_aS_1-aWherein x is more than or equal to 0 and less than or equal to 1, x is monotonically increased from 0 to 1 from inside to outside, and a is more than or equal to 0 and less than or equal to 1.

Example 10: preparation of blue quantum dot with quantum well energy level structure

Preparing cadmium oleate and zinc oleate precursors: 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 and vacuum degassed at 80 ℃ for 60 min. It was then switched to a nitrogen atmosphere and stored at this temperature for future use.

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

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

0.2mmol of Selenium powder (Selenium powder) is dissolved in 1mL of Trioctylphosphine (Trioctylphosphine) to obtain a Trioctylphosphine selenide precursor.

Placing 0.6 mmol of cadmium oxide (CdO), 0.6mL of Oleic acid (Oleic acid) and 5.4 mL of Octadecene (1-octaecene) in a 100 mL three-neck flask, and heating and refluxing at 250 ℃ for 120 min under the atmosphere of nitrogen to obtain a transparent cadmium oleate precursor.

Heating cadmium oleate and zinc oleate precursors to 310 ℃ in a nitrogen atmosphere, quickly injecting the thiooctadecene precursors into a reaction system, and firstly generating Cd_xZn_1-xAnd S, after reacting for 10 min, continuously injecting the cadmium oleate precursor and the trioctylphosphine selenide precursor into the reaction system at the speed of 0.6 mmol/h and the speed of 0.6 mmol/h for 20 min respectively. And then continuously injecting the cadmium oleate precursor and the trioctylphosphine sulfide precursor into the reaction system for 1 hour at the speed of 0.4 mmol/h and 6 mmol/h respectively. After the reaction is finished, after the reaction liquid is cooled to room temperature, repeatedly dissolving and precipitating the product by using toluene and absolute methanol, and centrifugally purifying to obtain the blue quantum dot (CdZnS/CdZnSe/CdZnS) with the quantum well energy level structure.

Example 11: preparation of green quantum dot with quantum well energy level structure

0.4 mmol of Selenium powder (Selenium powder) is dissolved in 2mL of Trioctylphosphine (Trioctylphosphine) to obtain a Trioctylphosphine selenide precursor.

Placing 0.8 mmol of cadmium oxide (CdO), 1.2 mL of Oleic acid (Oleic acid) and 4.8 mL of Octadecene (1-octaecene) in a 100 mL three-neck flask, and heating and refluxing at 250 ℃ for 120 min under the atmosphere of nitrogen to obtain a transparent cadmium oleate precursor.

Heating cadmium oleate and zinc oleate precursors to 310 ℃ in a nitrogen atmosphere, quickly injecting the thiooctadecene precursors into a reaction system, and firstly generating Cd_xZn_1-xAnd S, after reacting for 10 min, continuously injecting the cadmium oleate precursor and the trioctylphosphine selenide precursor into the reaction system for 40 min at the speed of 0.6 mmol/h and 0.6 mmol/h respectively. And then continuously injecting the cadmium oleate precursor and the trioctylphosphine sulfide precursor into the reaction system for 1 hour at the speed of 0.4 mmol/h and 6 mmol/h respectively. After the reaction is finished, after the reaction liquid is cooled to room temperature, repeatedly dissolving and precipitating the product by using toluene and absolute methanol, and centrifugally purifying to obtain the green quantum dot (CdZnS/CdZnSe/CdZnS) with the quantum well energy level structure.

Example 12: preparation of red quantum dot with quantum well energy level structure

Preparing cadmium oleate and zinc oleate precursors: 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 and vacuum degassed at 80 ℃ for 60 min. It was then switched to a nitrogen atmosphere and stored at this temperature for future use.

Dissolving 1.5 mmol Selenium powder (Selenium powder) and 1.75 mmol Sulfur powder (Sulfur powder) in 3mL Trioctylphosphine (Trioctylphosphine) to obtain the precursor 1 of Trioctylphosphine selenide-Trioctylphosphine sulfide.

1 mmol Selenium powder (Selenium powder) is added into 2mL Trioctylphosphine (Trioctylphosphine) to obtain the precursor of Trioctylphosphine selenide.

Dissolving 0.2mmol Selenium powder (Selenium powder) and 0.8 mmol Sulfur powder (Sulfur powder) in 2mL Trioctylphosphine (Trioctylphosphine) to obtain the precursor 2 of Trioctylphosphine selenide-Trioctylphosphine sulfide.

Placing 3 mmol of cadmium oxide (CdO), 3mL of Oleic acid (Oleic acid) and 6mL of Octadecene (1-octaecene) in a 100 mL three-neck flask, and heating and refluxing at 250 ℃ for 120 min under the atmosphere of nitrogen to obtain a transparent cadmium oleate precursor.

Heating cadmium oleate and zinc oleate precursors to 310 ℃ in the nitrogen atmosphere, injecting trioctylphosphine selenide-trioctylphosphine sulfide precursor 1 into a reaction system, and firstly generating Cd_xZn_1-xSe, after reacting for 10 min, dropwise adding 2mL of trioctylphosphine selenide precursor and 3mL of cadmium oleate precursor into the reaction system at the rates of 4 mL/h and 6 mL/h respectively. When the solution is injected for 30 min, 2mL of trioctylphosphine selenide-trioctylphosphine sulfide precursor 2 and 3mL of cadmium oleate precursor are respectively added into the reaction system drop by drop at the speed of 2 mL/h and 3 mL/h. After the reaction is finished, after the reaction liquid is cooled to room temperature, repeatedly dissolving and precipitating the product by using toluene and anhydrous methanol, and centrifugally purifying to obtain the red quantum dot (Cd) with the quantum well energy level structure_xZn_1- _xSe/CdZnSe/Cd_zZn_1-zSeS）。

Example 13

The quantum dot light emitting diode of the embodiment, as shown in fig. 2, sequentially includes from bottom to top: ITO substrate 11, bottom electrode 12, PEDOT: PSS hole injection layer 13, poly-TPD hole transport layer 14, quantum dot light emitting layer 15, ZnO electron transport layer 16 and Al top electrode 17.

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

a bottom electrode 12, a 30 nm PEDOT: after the PSS hole injection layer 13 and the 30 nm poly-TPD hole transport layer 14, a quantum dot light emitting layer 15 with the thickness of 20 nm is prepared on the poly-TPD hole transport layer 14, and then a 40 nm ZnO electron transport layer 16 and a 100 nm Al top electrode 17 are prepared on the quantum dot light emitting layer 15. The alloy material of the quantum dot light emitting layer 15 is the alloy material described in example 10.

Example 14

In this embodiment, the quantum dot light emitting diode, as shown in fig. 3, sequentially includes from bottom to top: ITO substrate 21, bottom electrode 22, PEDOT: PSS hole injection layer 23, Poly (9-vinylcarbazole) (PVK) hole transport layer 24, quantum dot light emitting layer 25, ZnO electron transport layer 26 and Al top electrode 27.

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

a bottom electrode 22, a 30 nm PEDOT: after the PSS hole injection layer 23 and the 30 nm PVK hole transport layer 24, a quantum dot light emitting layer 25 with the thickness of 20 nm is prepared on the PVK hole transport layer 24, and then a 40 nm ZnO electron transport layer 26 and a 100 nm Al top electrode 27 are prepared on the quantum dot light emitting layer 25. The alloy material of the quantum dot light emitting layer 25 is the alloy material described in example 11.

Example 15

The quantum dot light emitting diode of the embodiment, as shown in fig. 4, sequentially includes from bottom to top: ITO substrate 31, bottom electrode 32, PEDOT: PSS hole injection layer 33, poly-TPD hole transport layer 34, quantum dot light emitting layer 35, TPBi electron transport layer 36, and Al top electrode 37.

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

a bottom electrode 32, a 30 nm PEDOT: after the PSS hole injection layer 33 and the 30 nm poly-TPD hole transport layer 34, a quantum dot light emitting layer 35 with the thickness of 20 nm is prepared on the poly-TPD hole transport layer 34, and then a 30 nm TPBi electron transport layer 36 and a 100 nm Al top electrode 37 are prepared on the quantum dot light emitting layer 35 through a vacuum evaporation method. The alloy material of the quantum dot light emitting layer 35 is the alloy material described in example 12.

Example 16

The quantum dot light emitting diode of the embodiment, as shown in fig. 5, sequentially includes from bottom to top: ITO substrate 41, bottom electrode 42, ZnO electron transport layer 43, quantum dot light emitting layer 44, NPB hole transport layer 45, MoO₃A hole injection layer 46 and an Al top electrode 47.

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

preparing a bottom electrode 42, 40 nm ZnO on an ITO substrate 41 in sequenceAn electron transport layer 43, a quantum dot light emitting layer 44 is prepared on the ZnO electron transport layer 43, the thickness is 20 nm, and then a 30 nm NPB hole transport layer 45, 5 nm MoO is prepared by a vacuum evaporation method₃A hole injection layer 46 and a 100 nm Al top electrode 47. The alloy material of the quantum dot light emitting layer 44 is the alloy material described in example 10.

Example 17

The quantum dot light emitting diode of the present embodiment, as shown in fig. 6, sequentially includes from bottom to top: glass substrate 51, Al electrode 52, PEDOT: PSS hole injection layer 53, poly-TPD hole transport layer 54, quantum dot light emitting layer 55, ZnO electron transport layer 56, and ITO top electrode 57.

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

a 100 nm Al electrode 52 was prepared on a glass substrate 51 by a vacuum evaporation method, and then 30 nm PEDOT: after the PSS hole injection layer 53 and the 30 nm poly-TPD hole transport layer 54, a quantum dot light emitting layer 55 is prepared on the poly-TPD hole transport layer 54, the thickness is 20 nm, then a 40 nm ZnO electron transport layer 56 is prepared on the quantum dot light emitting layer 55, and finally 120 nm ITO is prepared through a sputtering method to serve as a top electrode 57. The alloy material of the quantum dot light emitting layer 55 is the alloy material described in example 11.

Example 18

The quantum dot light emitting diode of the embodiment, as shown in fig. 7, sequentially includes from bottom to top: 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, MoO₃A hole injection layer 66 and an ITO top electrode 67.

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

preparing a 100 nm Al electrode 62 on a glass substrate 61 by a vacuum evaporation method, then sequentially preparing a 40 nm ZnO electron transport layer 63 and a 20 nm quantum dot light emitting layer 64, and then preparing a 30 nm NPB hole transport layer 65 and a 5 nm MoO by the vacuum evaporation method₃A hole injection layer 66 and finally 120 nm ITO as a top electrode 67 were prepared by a sputtering method. The alloy material of the quantum dot light-emitting layer is the alloy material described in example 12。

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.

Claims

1. The alloy material with the quantum well energy level structure is characterized by comprising N structural units which are sequentially arranged in the radial direction, wherein N is more than or equal to 2;

the energy levels of adjacent building blocks are discontinuous.

2. The alloy material as claimed in claim 1, wherein the energy level width of the structural unit near the center of the alloy material is smaller than the energy level width of the structural unit far from the center of the alloy material.

3. The alloy material of claim 1, wherein the structural units are graded alloy composition structures comprising group II and group VI elements.

4. The alloy material of claim 3, wherein the alloying constituent of the structural elements is Cd_xZn_1- _xSe_yS_1-yWherein x is not less than 0 and not more than 1, y is not less than 0 and not more than 1, and x and y are not 0 and not 1 at the same time.

5. The alloy material as claimed in claim 4, wherein the alloy component at the point A in the structural unit is Cd_x ^AZn_1-x ^ASe_y ^AS_1-y ^AThe alloy component at the B point is Cd_x ^BZn_1-x ^BSe_y ^BS_1-y ^BWherein point A is more than point BClose to the center of the alloy material, and the compositions of the points A and B meet the following conditions:_x ^A＞_x ^B，_y ^A＞_y ^B。

6. the alloy material of claim 1, wherein the structural unit comprises 2-20 monoatomic layers or the structural unit comprises 1-10 unit cell layers.

7. The alloy material of claim 6, wherein an abrupt structure is formed between two monoatomic layers at the interface of the structural units adjacent in the radial direction, or an abrupt structure is formed between two unit cell layers at the interface of the structural units adjacent in the radial direction.

8. The alloy material according to claim 1, wherein the alloy material has a light emission peak wavelength ranging from 400 nm to 700 nm.

9. The alloy material according to claim 1, wherein a half-height peak width of a light emission peak of the alloy material is 12 nm to 80 nm.

10. A method for preparing the alloy material of claim 1, comprising the steps of:

synthesizing a first compound at a predetermined position;

11. The method of claim 10, wherein the cationic precursor of the first compound and/or the second compound comprises a Zn precursor, and the Zn precursor is at least one of dimethyl zinc, diethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc oleate, or zinc stearate.

12. The method according to claim 10, wherein the cation precursor of the first compound and/or the second compound comprises a precursor of Cd, and the precursor of Cd is at least one of cadmium dimethyl, cadmium diethyl, cadmium acetate, cadmium acetylacetonate, cadmium iodide, cadmium bromide, cadmium chloride, cadmium fluoride, cadmium carbonate, cadmium nitrate, cadmium oxide, cadmium perchlorate, cadmium phosphate, cadmium sulfate, cadmium oleate, or cadmium stearate.

13. The method of claim 10, wherein the anionic precursor of the first compound and/or the second compound comprises a precursor of Se, wherein the precursor of Se is at least one of Se-TOP, Se-TBP, Se-TPP, Se-ODE, Se-OA, Se-ODA, Se-TOA, Se-ODPA, or Se-OLA.

14. The method of claim 10, wherein the anionic precursor of the first compound and/or the second compound comprises a precursor of S, and the precursor of S is at least one of S-TOP, S-TBP, S-TPP, S-ODE, S-OA, S-ODA, S-TOA, S-ODPA, S-OLA, or an alkyl thiol.

15. The method for preparing an alloy material according to claim 10, wherein the anion precursor of the first compound and/or the second compound comprises a precursor of Te, and the precursor of Te is at least one of Te-TOP, Te-TBP, Te-TPP, Te-ODE, Te-OA, Te-ODA, Te-TOA, Te-ODPA, or Te-OLA.

16. The method for producing an alloy material according to claim 10, wherein a cation exchange reaction occurs between the first compound and the second compound under heating.

17. The method of claim 16, wherein the heating temperature is between 100 ℃ and 400 ℃.

18. Method for the preparation of an alloy material according to claim 16, characterized in that the heating time is between 2s and 24 h.

19. The method of claim 10, wherein the molar ratio of the cationic precursor to the anionic precursor is between 100:1 and 1:50 during the synthesis of the first compound.

20. The method of claim 10, wherein the molar ratio of the cationic precursor to the anionic precursor is between 100:1 and 1:50 during the synthesis of the second compound.

21. A semiconductor device comprising the alloy material according to any one of claims 1 to 9.

22. The semiconductor device according to claim 21, wherein the semiconductor device is any one of an electroluminescent device, a photoluminescent device, a solar cell, a display device, a photodetector, a biological probe, and a nonlinear optical device.