Blue-light znsete core-shell quantum dots and preparation method therefor, and display device

Abstract

Blue-light ZnSeTe core-shell quantum dots and a preparation method therefor, and a display device. The blue-light ZnSeTe core-shell quantum dots are well formed, and have few defects and a narrow emission line width, and the photoluminescence performance and the performance of an electroluminescent apparatus are significantly improved. The preparation method comprises the steps of: S1, preparation of a core body: adding an activity enhancer, a selenium precursor, a tellurium precursor and a zinc precursor at 220-260°C, and mixing and reacting same to form a blue-light ZnSeTe core body; S2, preparation of a transition layer: adding an etching agent to S1, and etching the blue-light ZnSeTe core body; and after heating, adding a zinc precursor and a selenium precursor, wherein the selenium precursor is added dropwise at a speed of 4-6 mL / h, so as to form a ZnSe transition layer coating the blue-light ZnSeTe core body; and S3, preparation of a shell layer: after cooling, adding a zinc precursor and a sulfur precursor to S2, the zinc precursor being an amine-containing zinc precursor, and thereby forming a ZnS shell layer coating the transition layer.

Description

A blue light ZnSeTe core-shell quantum dot and its preparation method and display device Technical Field

[0001] The present application belongs to the technical field of quantum dots, and specifically relates to a blue light ZnSeTe core-shell quantum dot and a preparation method and a display device thereof. Background Art

[0002] Quantum dots, also known as semiconductor nanocrystals, are a new type of semiconductor nanomaterial with sizes ranging from 1 to 10 nm. Due to quantum size effects and dielectric confinement, they possess unique photoluminescence (PL) and electroluminescence (EL) properties. Compared to traditional organic fluorescent dyes, quantum dots offer excellent optical properties such as high quantum yield, high photochemical stability, resistance to photolysis, broad excitation, narrow emission, high color purity, and tunable luminescence color by controlling quantum dot size. These properties hold broad application prospects in display technology.

[0003] Currently, cadmium-based quantum dots (QDs) have gradually begun commercialization due to their advantages of high quantum efficiency, small half-width (FWHM), strong blue light absorption, and good stability. However, due to the presence of the heavy metal cadmium, these QDs no longer meet the increasingly important environmental protection requirements, making the development of new cadmium-free QDs extremely urgent. Environmentally friendly QDs include: InP-based, carbon dots, perovskites, AgS, PbS, ZnO, ZnSe, ZnSeTe, etc. However, compared with traditional cadmium-based QDs, existing environmentally friendly QDs have many shortcomings, such as poor blue light absorption, large FWHM, and poor stability, which limit their application.

[0004] Among them, high-color-purity blue ZnSeTe quantum dots have great potential applications in light-emitting diodes and other ultra-high-definition displays. However, achieving blue ZnSeTe quantum dots with narrow emission linewidth and high luminous efficiency remains a major challenge. Current blue ZnSeTe quantum dots have a relatively large electroluminescent linewidth, and their luminous efficiency needs to be improved.

[0005] In view of this, the present application provides a blue light ZnSeTe core-shell quantum dot and its preparation method and display device. The blue light ZnSeTe core-shell quantum dot has good shape, few defects, narrow emission linewidth, and significantly improved photoluminescence performance and electroluminescent device performance.

[0006] Summary of the Invention

[0007] The purpose of this application is to provide a blue light ZnSeTe core-shell quantum dot and its preparation method and display device. The blue light ZnSeTe core-shell quantum dot has good shape, few defects, narrow emission linewidth, and significantly improved photoluminescence performance and electroluminescent device performance.

[0008] In a first aspect of the present application, a method for preparing blue-light ZnSeTe core-shell quantum dots is provided, the method comprising the steps of:

[0009] S1, preparing the nucleus: adding an activity enhancer, a selenium precursor, a tellurium precursor and a zinc precursor and reacting them at 220-260°C to form a blue light-emitting ZnSeTe nucleus;

[0010] S2, preparing a transition layer: adding an etchant to S1 to etch the blue-light ZnSeTe core; after heating, adding a zinc precursor and a selenium precursor, wherein the selenium precursor is added dropwise at a rate of 4-6 mL / h to form a ZnSe transition layer covering the blue-light ZnSeTe core;

[0011] S3, preparing an outer shell layer: after cooling, adding a zinc precursor and a sulfur precursor to S2, wherein the zinc precursor is an amine-containing zinc precursor, to form a ZnS outer shell layer covering the transition layer.

[0012] In some embodiments, in step S1, fatty acid, oily ligand and organic solvent are first added, vacuum is applied, inert gas is introduced for protection, and then the temperature is raised to 220-260°C.

[0013] In some embodiments, the activity enhancer is used to enhance the reactivity of the selenium precursor and the tellurium precursor.

[0014] Furthermore, the activity enhancer includes at least one of diphenylphosphine (DPP), triphenylphosphine, tributylphosphine (TBP), and tripentylphosphine.

[0015] Furthermore, the molar ratio of the activity enhancer to the selenium precursor is (3-6): 1. Preferably, the molar ratio of the activity enhancer to the selenium precursor is (4-5.5): 1.

[0016] In some embodiments, in step S1, the molar ratio of the tellurium precursor, the selenium precursor, and the zinc precursor added is 1:(20-30):(40-60). Preferably, the molar ratio of the tellurium precursor, the selenium precursor, and the zinc precursor added is 1:(23-25):(45-55).

[0017] Furthermore, at 220-260° C., an activity enhancer, a selenium precursor, and a tellurium precursor are first added and reacted for 3-7 minutes, and then a zinc precursor is added and reacted for 20-30 minutes to form a blue light ZnSeTe core.

[0018] Furthermore, the diameter of the blue light ZnSeTe core is 4.1-4.5 nm.

[0019] In some embodiments, the etchant includes at least one of hydrofluoric acid, phenylcarbonyl fluoride, sodium fluoride, lead tetrafluoride, aluminum fluoride, tetrabutylammonium fluoride, and cesium fluoride.

[0020] In some embodiments, in step S2, after heating to 300-330°C, a zinc precursor and a selenium precursor are added, and the molar ratio of the selenium precursor to the zinc precursor is 1:(1.5-4). Preferably, the molar ratio of the selenium precursor to the zinc precursor is 1:(1.5-2.5).

[0021] Further, when the temperature reaches 300-330° C., 2 / 5-4 / 5 of the zinc precursor is added, and then the selenium precursor is added dropwise at a rate of 4-6 mL / h. When the selenium precursor is added to half, the remaining zinc precursor is added.

[0022] Furthermore, the thickness of the ZnSe transition layer is 2.4-2.6 nm.

[0023] In some embodiments, in step S2, after forming the ZnSe transition layer, the temperature is raised to 320-340°C, and a zinc precursor and a sulfur precursor are added to form a ZnSe coating. 1-x S x Transition layer, 0<X<1; wherein the molar ratio of the added sulfur precursor to the zinc precursor is 1:(1.5-4), and the sulfur precursor is added dropwise at a rate of 6-10 mL / h. Preferably, the molar ratio of the added sulfur precursor to the zinc precursor is 1:(1.5-2.5).

[0024] Further, when the temperature reaches 310-340° C., 2 / 5-4 / 5 of the zinc precursor is added, and then the sulfur precursor is added dropwise at a rate of 6-10 mL / h. When the sulfur precursor is added to half, the remaining zinc precursor is added.

[0025] Furthermore, the thickness of the ZnSe1-xSx transition layer is 0.25-0.35 nm.

[0026] In some embodiments, in step S3, the amine-containing zinc precursor and the sulfur precursor are added after the temperature is lowered to 240-290° C., and the amine-containing zinc precursor is added dropwise at a rate of 22-26 mL / h, while the sulfur precursor is added dropwise at a rate of 4-8 mL / h to form a ZnS outer shell layer.

[0027] Furthermore, the molar ratio of the sulfur precursor to the amine-containing zinc precursor is 1:(0.8-3). Preferably, the molar ratio of the sulfur precursor to the amine-containing zinc precursor is 1:(0.8-1.5).

[0028] In some embodiments, the preparation method further comprises step S4, adding the amine-containing zinc precursor and thiol ligand to step S3 to increase the thickness of the ZnS outer shell layer.

[0029] Furthermore, in step S4, the amine-containing zinc precursor is added dropwise at a rate of 22-26 mL / h, and the thiol ligand is added dropwise at a rate of 2-5 mL / h.

[0030] Furthermore, the molar ratio of the thiol ligand to the amine-containing zinc precursor is 1:(0.8-3). Preferably, the molar ratio of the thiol ligand to the amine-containing zinc precursor is 1:(0.8-1.5).

[0031] Furthermore, the thickness of the ZnS outer shell layer is 0.7-0.9 nm.

[0032] In some embodiments, the maximum emission peak wavelength of the blue ZnSeTe core-shell quantum dots is 430-480 nm. Preferably, the maximum emission peak wavelength of the blue ZnSeTe core-shell quantum dots is 440-460 nm. More preferably, the maximum emission peak wavelength of the blue ZnSeTe core-shell quantum dots is 445-455 nm.

[0033] Furthermore, the blue light ZnSeTe core-shell quantum dots are cube-like or tetrahedral-like.

[0034] In a second aspect of the present application, a blue-light ZnSeTe core-shell quantum dot is provided, wherein the blue-light ZnSeTe core-shell quantum dot is obtained by the above-mentioned preparation method.

[0035] In some embodiments, the diameter of the blue light ZnSeTe core is 4.1-4.5 nm, the thickness of the ZnSe transition layer is 2.4-2.6 nm, the thickness of the ZnSe1-xSx transition layer is 0.25-0.35 nm, and the thickness of the ZnS outer shell is 0.7-0.9 nm.

[0036] In some embodiments, the maximum emission peak wavelength of the blue ZnSeTe core-shell quantum dots is 430-480 nm. Preferably, the maximum emission peak wavelength of the blue ZnSeTe core-shell quantum dots is 440-460 nm. More preferably, the maximum emission peak wavelength of the blue ZnSeTe core-shell quantum dots is 445-455 nm.

[0037] Furthermore, the blue light ZnSeTe core-shell quantum dots are cube-like or tetrahedral-like.

[0038] In a third aspect of the present application, a display device is provided, comprising the above-mentioned blue light ZnSeTe core-shell quantum dots.

[0039] The blue light ZnSeTe core-shell quantum dots and their preparation method of the present application have at least the following advantages compared with the prior art:

[0040] (1) When synthesizing the blue-light ZnSeTe core, the present invention adds an activity enhancer to increase the reactivity of the selenium precursor and the tellurium precursor, making the distribution of Se and Te in the ZnSeTe core more uniform, reducing the half-peak width of the blue-light ZnSeTe core-shell quantum dots, and improving the photoluminescence performance and electroluminescent device performance of the blue-light ZnSeTe core-shell quantum dots. On this basis, the mass ratio of the added selenium precursor, tellurium precursor, and zinc precursor is controlled, so that the selenium precursor, tellurium precursor, and zinc precursor react almost completely while the ZnSeTe core emits blue light, eliminating the need for purification and extraction steps, thereby greatly simplifying the synthesis steps.

[0041] (2) Before synthesizing the ZnSe transition layer, the present invention first uses an etchant to etch the blue-light ZnSeTe core, significantly reducing the surface oxidation state of the blue-light ZnSeTe core. Furthermore, the additional fluoride ions can also serve as surface ligands to enhance hole transport in the QLED. Furthermore, the prepared blue-light ZnSeTe core-shell quantum dots are quasi-cubic or quasi-tetrahedral, rather than quasi-spherical.

[0042] (3) When synthesizing the ZnSe transition layer in the present application, the selenium precursor is added dropwise at a certain speed, the transition of the gradient alloy layer is very slow, the lattice adaptability is better and more stable, and at the same time, the stress is smaller and the transition layer defects are fewer, making the reaction more complete and the thickness of the transition layer increased.

[0043] (4) This application also sets ZnSe on the ZnSe transition layer 1-x S x The transition layer makes the band gap energy increase more smoothly, that is, the lattice adaptability is better and more stable, the lattice defects are fewer, and the optical properties are better. At the same time, the sulfur precursor is added dropwise at a certain speed, ZnSe 1-x S x The band gap energy of the transition layer slowly increases, further improving the optical performance.

[0044] (5) In the preparation of the ZnS shell layer, the zinc precursor is an amine-containing zinc precursor, which increases the reaction activity and facilitates the growth of the shell layer. Furthermore, after the synthesis is completed and the temperature is cooled to room temperature, the oleic acid ligand replaces the amine substance in the amine-containing zinc precursor, and the oleic acid ligand binds more strongly to the quantum dots at room temperature.

[0045] (6) After preparing the ZnS shell layer, the present application continues to add step S4 to increase the thickness of the ZnS shell layer; at the same time, the binding force between the thiol ligand and the quantum dots is stronger, thereby increasing the coverage and binding strength of the ligand. DETAILED DESCRIPTION

[0046] The following examples are described to assist in understanding the present application, and the examples are not and should not be interpreted in any way as limiting the scope of protection of the present application.

[0047] As used herein, for example, "at least one of" when preceding or following a list of elements modifies the entire list of elements without modifying the individual elements of the list. If not otherwise defined, all terms (including technical and scientific terms) in the specification may be defined as those skilled in the art would normally understand. Terms defined in commonly used dictionaries should be interpreted as being consistent with their meanings in the context of the relevant art and the present disclosure, and should not be interpreted in an ideal manner or too broadly unless clearly defined. In addition, unless explicitly described to the contrary, the phrases "comprise" and "comprising" when used in this specification indicate the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or sets thereof. Therefore, the above phrases will be understood to mean including the stated elements, but not excluding any other elements.

[0048] In a first aspect of the present application, a method for preparing blue-light ZnSeTe core-shell quantum dots is provided, the method comprising the steps of:

[0049] S1, preparing the nucleus: adding an activity enhancer, a selenium precursor, a tellurium precursor and a zinc precursor and reacting them at 220-260°C to form a blue light-emitting ZnSeTe nucleus;

[0050] S2, preparing a transition layer: adding an etchant to S1 to etch the blue-light ZnSeTe core; after heating, adding a zinc precursor and a selenium precursor, wherein the selenium precursor is added dropwise at a rate of 4-6 mL / h to form a ZnSe transition layer covering the blue-light ZnSeTe core;

[0051] S3, preparing an outer shell layer: after cooling, adding a zinc precursor and a sulfur precursor to S2, wherein the zinc precursor is an amine-containing zinc precursor, to form a ZnS outer shell layer covering the transition layer.

[0052] In some embodiments, in step S1, fatty acid, oily ligand and organic solvent are first added, vacuum is applied, inert gas is introduced for protection, and then the temperature is raised to 220-260°C.

[0053] Furthermore, fatty acids, oily ligands and organic solvents are first added, vacuumed, and the temperature is raised to 100-140°C, for example, 100°C, 110°C, 120°C, 130°C or 140°C, but not limited to the listed values. Other values ​​not listed within the above range are also applicable. Then, inert gas protection is introduced, and the temperature is then raised to 220-260°C, for example, 220°C, 230°C, 240°C, 250°C or 260°C, but not limited to the listed values. Other values ​​not listed within the above range are also applicable.

[0054] The fatty acid includes at least one of palmitic acid (PA), oleic acid, stearic acid, lauric acid, and undecylenic acid.

[0055] The oily ligand includes at least one of oleylamine (OlAm), n-octylamine, tetradecylamine, and hexadecylamine.

[0056] The organic solvent includes at least one of trioctylamine (TOA), hexadecylamine, dioctylamine, hexadecane, octadecane, squalane, phenyldodecane, phenyltetradecane, and phenylhexadecane.

[0057] In some embodiments, the activity enhancer is used to enhance the reactivity of the selenium precursor and the tellurium precursor.

[0058] Furthermore, the activity enhancer includes at least one of diphenylphosphine (DPP), triphenylphosphine, tributylphosphine (TBP), and tripentylphosphine.

[0059] Furthermore, the molar ratio of the activity enhancer to the selenium precursor is (3-6): 1. Preferably, the molar ratio of the activity enhancer to the selenium precursor is (4-5.5): 1, for example, 4: 1, 4.2: 1, 4.5: 1, 5: 1, 5.2: 1 or 5.5: 1, but is not limited to the listed values, and other values ​​within the above range that are not listed are also applicable.

[0060] The present application adds an activity enhancer when synthesizing a blue-light ZnSeTe core. The activity enhancer is used to enhance the reactivity of the selenium precursor and the tellurium precursor, making the distribution of Se and Te in the ZnSeTe core more uniform, resulting in a smaller half-width at half-maximum of the blue-light ZnSeTe core-shell quantum dots, and improving the crystallinity of the ZnSeTe core (fewer defects), i.e., improving the photoluminescence performance and electroluminescent device performance of the blue-light ZnSeTe core-shell quantum dots. At the same time, due to the enhanced activity of the selenium precursor and the tellurium precursor, the reaction temperature can be 220-260°C, which is lower than the reaction temperature of the conventional ZnSeTe core; and it is not recommended to exceed 260°C to avoid difficulty in control due to excessive reactivity.

[0061] In some embodiments, in step S1, the molar ratio of the tellurium precursor, the selenium precursor, and the zinc precursor is 1:(20-30):(40-60). Preferably, the molar ratio of the tellurium precursor, the selenium precursor, and the zinc precursor is 1:(23-25):(45-55), for example, 1:23:45, 1:24:50, or 1:25:55, but is not limited to the listed values, and other values ​​within the above ranges not listed are also applicable.

[0062] When synthesizing the blue-light ZnSeTe core in the present application, in addition to adding an activity enhancer, the mass ratio of the added selenium precursor, tellurium precursor, and zinc precursor is controlled. On the one hand, this allows the ZnSeTe core to emit blue light, and on the other hand, the selenium precursor, tellurium precursor, and zinc precursor react almost completely, eliminating the need for purification and extraction steps and having no effect on the subsequent shell synthesis, thereby simplifying the synthesis steps.

[0063] Further, at 220-260°C, for example, 220°C, 230°C, 240°C, 250°C or 260°C, but not limited to the listed values, other values ​​not listed in the above range are also applicable, first add the activity enhancer, selenium precursor and tellurium precursor, react for 3-7 minutes, for example, 3 minutes, 4 minutes, 5 minutes, 6 minutes or 7 minutes, but not limited to the listed values, other values ​​not listed in the above range are also applicable, then add the zinc precursor, react for 20-30 minutes, for example, 20 minutes, 25 minutes or 30 minutes, but not limited to the listed values, other values ​​not listed in the above range are also applicable, to form a blue light ZnSeTe core.

[0064] The selenium precursor includes at least one of selenium-trioctylphosphine (Se-TOP), selenium-tributylphosphine (Se-TBP), selenium-triphenylphosphine (Se-TPP), and selenium-diphenylphosphine (Se-DPP).

[0065] The tellurium precursor includes at least one of tellurium-trioctylphosphine (Te-TOP), tellurium-tributylphosphine (Te-TBP), and tellurium-triphenylphosphine (Te-TPP).

[0066] The zinc precursor includes: Zn powder, ZnO, and an alkylated Zn compound, wherein the alkylated Zn compound includes: at least one of C2-C30 dialkyl zinc, Zn alkoxide, Zn carboxylate, Zn nitrate, Zn perchlorate, Zn sulfate, Zn acetylacetonate, Zn halide, Zn cyanide, Zn hydroxide, zinc carbonate, and zinc peroxide. The zinc precursor includes: 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 oleate, zinc peroxide, zinc perchlorate, zinc palmitate, zinc laurate, zinc n-hexanoate, and zinc sulfate.

[0067] Furthermore, the diameter of the blue light ZnSeTe core is 4.1-4.5 nm, for example, 4.1 nm, 4.2 nm, 4.3 nm, 4.4 nm or 4.5 nm, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0068] In some embodiments, the etchant includes a fluoride, and the fluoride includes at least one of hydrofluoric acid, phenylcarbonyl fluoride, sodium fluoride, lead tetrafluoride, aluminum fluoride, tetrabutylammonium fluoride, and cesium fluoride.

[0069] By using an etchant to etch the blue-light ZnSeTe core, the surface oxidation state of the blue-light ZnSeTe core is greatly reduced, thereby improving the performance of the final quantum dot product. At the same time, the additional fluoride ions can also act as surface ligands to reduce the amount of carboxylic acid ligands on the surface of the quantum dots, which is beneficial to hole transport in QLEDs.

[0070] In some embodiments, in step S2, after heating to 300-330°C, a zinc precursor and a selenium precursor are added, for example, 300°C, 310°C, 320°C or 330°C, but not limited to the listed values, and other values ​​not listed within the above range are also applicable; the molar ratio of the selenium precursor to the zinc precursor is 1: (1.5-4), for example, 1:1.5, 1:2.0, 1:2.5, 1:3.0, 1:3.5 or 1:4, but not limited to the listed values, and other values ​​not listed within the above range are also applicable. Preferably, the molar ratio of the selenium precursor to the zinc precursor is 1: (1.5-2.5), for example, 1:1.5, 1:2.0 or 1:2.5, but not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0071] Further, when the temperature reaches 300-330°C, 2 / 5-4 / 5 of the zinc precursor is added, for example, 2 / 5, 3 / 5 or 4 / 5, but not limited to the listed values, and other values ​​not listed within the above range are also applicable; then the selenium precursor is added dropwise at a rate of 4-6 mL / h, for example, 4 mL / h, 5 mL / h or 6 mL / h, but not limited to the listed values, and other values ​​not listed within the above range are also applicable. When the selenium precursor is added halfway, the remaining zinc precursor is added.

[0072] Furthermore, the thickness of the ZnSe transition layer is 2.4-2.6 nm, for example, 2.4 nm, 2.5 nm or 2.6 nm, but is not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0073] When preparing the ZnSe transition layer, the present application drips the selenium precursor at a speed of 4-6mL / h, for example, 4mL / h, 5mL / h or 6mL / h, but is not limited to the numerical values ​​listed, and other numerical values ​​not listed within the above range are equally applicable, and the transition layer grows little by little, and the transition of the gradient alloy layer is very slow. The band gap energy value of the transition layer is between the core and the shell layer, thereby increasing the lattice adaptability. The present application makes the transition layer grow slowly, and the band gap energy grows in a curve (such as the LM curve), so that the increase of the band gap energy is slower, that is, the lattice adaptability is better and more stable, while making the stress smaller and the transition layer defect less, so that the reaction is more sufficient and the thickness of the transition layer increases.

[0074] In some embodiments, in step S2, after forming the ZnSe transition layer, the temperature is raised to 320-340°C, for example, 320°C, 330°C or 340°C, but not limited to the values ​​listed above, and other values ​​not listed within the above range are also applicable; a zinc precursor and a sulfur precursor are added to form a ZnSe coating with a ZnSe transition layer. 1-x S x Transition layer, 0<X<1; wherein the molar ratio of the added sulfur precursor to the zinc precursor is 1:(1.5-4), for example, 1:1.5, 1:2.0, 1:2.5, 1:3.0, 1:3.5, or 1:4, but not limited to the listed values, other values ​​not listed within the above range are also applicable, and the sulfur precursor is added dropwise at a rate of 6-10 mL / h. Preferably, the molar ratio of the added sulfur precursor to the zinc precursor is 1:(1.5-2.5), for example, 1:1.5, 1:2.0, or 1:2.5, but not limited to the listed values, other values ​​not listed within the above range are also applicable.

[0075] Further, the temperature reaches 310-340° C., for example, 310° C., 320° C., 330° C. or 340° C., but not limited to the listed values, and other values ​​not listed within the above range are also applicable; 2 / 5-4 / 5 of the zinc precursor is added, for example, 2 / 5, 3 / 5 or 4 / 5, but not limited to the listed values, and other values ​​not listed within the above range are also applicable; then the sulfur precursor is added dropwise at a rate of 6-10 mL / h, for example, 6 mL / h, 7 mL / h, 8 mL / h, 9 mL / h or 10 mL / h, but not limited to the listed values, and other values ​​not listed within the above range are also applicable. When the sulfur precursor is halfway added, the remaining zinc precursor is added.

[0076] The sulfur precursor includes at least one of hexyl mercaptan, octyl mercaptan, decanethiol, dodecanethiol, hexadecanethiol, mercaptopropylsilane, sulfur-trioctylphosphine (S-TOP), sulfur-tributylphosphine (S-TBP), sulfur-triphenylphosphine (S-TPP), sulfur-trioctylamine (S-TOA), bis(trimethylsilyl)sulfide, ammonium sulfide, and sodium sulfide.

[0077] Furthermore, the thickness of the ZnSe1-xSx transition layer is 0.25-0.35 nm, for example, 0.25 nm, 0.30 nm or 0.35 nm, but is not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0078] On the one hand, since the amount of selenium precursor added in the synthesis of the ZnSe transition layer is excessive, the remaining selenium precursor participates in the ZnSe 1-x S x Synthesis of transition layer to form ZnSe 1-x S x On the other hand, high temperature causes Se in the ZnSe transition layer to migrate outward, participating in the ZnSe 1-x S x Synthesis of transition layer. And, with the ZnSe 1-x S x As the thickness of the transition layer increases, its X value increases (i.e. the proportion of S gradually increases). This application sets the ZnSe transition layer and ZnSe from the inside to the outside in sequence. 1-x S x The transition layer makes the band gap energy increase more gradually, that is, the lattice adaptability is better and more stable, the lattice defects are fewer, and the optical properties are better. At the same time, the sulfur precursor is added dropwise at a rate of 6-10 mL / h, for example, 6 mL / h, 7 mL / h, 8 mL / h, 9 mL / h or 10 mL / h, but not limited to the values ​​listed above. Other values ​​not listed in the above range are also applicable. ZnSe 1-x S xThe band gap energy of the transition layer slowly increases, further improving the optical performance.

[0079] In some embodiments, in step S3, the amine-containing zinc precursor and the sulfur precursor are added after cooling to 240-290°C, for example, 240°C, 250°C, 260°C, 270°C, 280°C or 290°C, but not limited to the listed values, other values ​​not listed within the above range are also applicable; the amine-containing zinc precursor is added dropwise at a rate of 22-26 mL / h, for example, 22 mL / h, 23 mL / h, 24 mL / h, 25 mL / h or 26 mL / h, but not limited to the listed values, other values ​​not listed within the above range are also applicable; and the sulfur precursor is added dropwise at a rate of 4-8 mL / h, for example, 4 mL / h, 5 mL / h, 6 mL / h, 7 mL / h or 8 mL / h, but not limited to the listed values, other values ​​not listed within the above range are also applicable, to form a ZnS outer shell layer.

[0080] Furthermore, the molar ratio of the sulfur precursor to the amine-containing zinc precursor is 1:(0.8-3), for example, 1:0.8, 1:1.0, 1:1.2, 1:1.5, 1:1.8, 1:2.0, 1:2.4, 1:2.6, 1:2.8, or 1:3, but is not limited to the values ​​listed above. Other values ​​not listed within the above range are also applicable. Preferably, the molar ratio of the sulfur precursor to the amine-containing zinc precursor is 1:(0.8-1.5), for example, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, or 1:1.5, but is not limited to the values ​​listed above. Other values ​​not listed within the above range are also applicable.

[0081] Furthermore, the amine-containing zinc precursor includes at least one of zinc oleylamine (Zn / OlAm), zinc n-octylamine, zinc tetradecylamine, and zinc hexadecylamine.

[0082] When preparing the ZnS shell layer, the reaction activity will be greatly reduced, and it is not easy to grow the shell layer. When preparing the ZnS shell layer in this application, the zinc precursor is an amine-containing zinc precursor. The amine-containing zinc precursor does not solidify in the dripping pipe (the temperature in the pipe is 25°C room temperature), so the amine-containing zinc precursor can be added dropwise to increase the reaction activity and make the shell layer easy to grow. In addition, after the synthesis is completed and the temperature is lowered to room temperature, the oleic acid ligand will replace the amine substance of the amine-containing zinc precursor, and the oleic acid ligand will be more strongly bound to the quantum dots at room temperature.

[0083] In some embodiments, the preparation method further comprises step S4, adding the amine-containing zinc precursor and thiol ligand to step S3 to increase the thickness of the ZnS outer shell layer.

[0084] Further, in step S4, the amine-containing zinc precursor is added dropwise at a rate of 22-26 mL / h, for example, 22 mL / h, 23 mL / h, 24 mL / h, 25 mL / h or 26 mL / h, but not limited to the listed values, and other values ​​not listed within the above range are also applicable; at the same time, the thiol ligand is added dropwise at a rate of 2-5 mL / h, for example, 2 mL / h, 3 mL / h, 4 mL / h or 5 mL / h, but not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0085] Furthermore, the molar ratio of the thiol ligand to the amine-containing zinc precursor is 1:(0.8-3), for example, 1:0.8, 1:1.0, 1:1.2, 1:1.5, 1:1.8, 1:2.0, 1:2.4, 1:2.6, 1:2.8 or 1:3, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable. Preferably, the molar ratio of the thiol ligand to the amine-containing zinc precursor is 1:(0.8-1.5), for example, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable.

[0086] Furthermore, the thickness of the ZnS outer shell layer is 0.7-0.9 nm, for example, 0.7 nm, 0.8 nm or 0.9 nm, but is not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0087] The thiol ligand includes at least one of methyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, pentyl mercaptan, hexyl mercaptan, octyl mercaptan, dodecanethiol, hexadecanethiol, octadecanethiol, and benzyl mercaptan.

[0088] After preparing the ZnS outer shell layer, the present application further adds step S4. On the one hand, the thiol ligand can be decomposed as a sulfur source to continue to generate ZnS, thereby increasing the thickness of the ZnS outer shell layer; on the other hand, the thiol ligand acts as a ligand with a stronger binding force than the oleic acid ligand, thereby increasing the coverage and binding firmness of the ligand.

[0089] In some embodiments, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 430-480 nm, for example, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm or 480 nm, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable. Preferably, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 440-460 nm, for example, 440 nm, 450 nm or 460 nm, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable. More preferably, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 445-455 nm, for example, 445 nm, 446 nm, 447 nm, 448 nm, 449 nm, 450 nm, 451 nm, 452 nm, 453 nm, 454 nm or 455 nm, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0090] Furthermore, the blue light ZnSeTe core-shell quantum dots are cube-like or tetrahedral-like.

[0091] The blue light ZnSeTe core-shell quantum dots of the present application are cube-like or tetrahedral (mainly due to the etching effect of the etchant on the core body and the role of the surface ligand), rather than spherical. The three-dimensional morphology is conducive to making the light-emitting layer of the blue light ZnSeTe core-shell quantum dots in QLED applications smoother, that is, better film-forming properties.

[0092] In a second aspect of the present application, a blue-light ZnSeTe core-shell quantum dot is provided, wherein the blue-light ZnSeTe core-shell quantum dot is prepared by the above method.

[0093] In some embodiments, the diameter of the blue light ZnSeTe core is 4.1-4.5 nm, for example, 4.1 nm, 4.2 nm, 4.3 nm, 4.4 nm or 4.5 nm, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable; the thickness of the ZnSe transition layer is 2.4-2.6 nm, for example, 2.4 nm, 2.5 nm or 2.6 nm, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable; the thickness of the ZnSe1-xSx transition layer is 0.25-0.35 nm, and the thickness of the ZnS outer shell layer is 0.7-0.9 nm, for example, 0.7 nm, 0.8 nm or 0.9 nm, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0094] In some embodiments, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 430-480 nm, for example, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm or 480 nm, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable. Preferably, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 440-460 nm, for example, 440 nm, 450 nm or 460 nm, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable. More preferably, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 445-455 nm, for example, 445 nm, 446 nm, 447 nm, 448 nm, 449 nm, 450 nm, 451 nm, 452 nm, 453 nm, 454 nm or 455 nm, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0095] Furthermore, the blue light ZnSeTe core-shell quantum dots are cube-like or tetrahedral-like.

[0096] In a third aspect of the present application, a display device is provided, comprising the above-mentioned blue light ZnSeTe core-shell quantum dots.

[0097] Display devices include: display equipment, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), quantum dot LEDs, quantum dot films, sensors, solar cells, image sensors, or liquid crystal displays (LCDs). Display devices include: electronic paper, mobile phones, tablets, televisions, monitors, laptops, digital photo frames, navigation systems, car displays, AR displays, and VR displays.

[0098] In addition to the core-shell quantum dot film, the display device may also include structures known to those skilled in the art in the technical field of the present invention. That is, the present invention includes a display device to which the core-shell quantum dot film of the present invention can be applied.

[0099] The present invention will be further described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. The implementation conditions adopted in the examples can be further adjusted according to different requirements of specific use, and the conditions not specified are conventional conditions in the industry.

[0100] Example 1:

[0101] Step S1: Preparation of nuclear bodies

[0102] To a 250mL three-necked flask, 1.02g of palmitic acid (PA, 4mmol / L), 5mL of oleylamine (OlAm), and 20mL of trioctylamine (TOA) were rapidly added. The mixture was evacuated and heated to 120°C, where it was maintained in vacuum for 2h. Ar was introduced, the reaction temperature was set to 240°C, and the temperature was increased. Once the temperature reached 240°C, 1mL of diphenylphosphine (DPP), 0.6mL of selenium-trioctylphosphine (Se-TOP, 2mol / L), and 0.5mL of tellurium-trioctylphosphine (Te-TOP, 0.1mol / L) were rapidly injected, followed by a 5min reaction. Then, 2.5mL of diethylzinc (DEZ, 1mol / L) was rapidly injected and the reaction continued for 25min, forming blue-emitting ZnSeTe cores.

[0103] Step S2: Preparation of ZnSe transition layer and ZnSe 1-x S x transition layer

[0104] 0.1 mL of hydrofluoric acid-acetone solution (HF-acetone, 10% HF, 90% acetone) was quickly added to the reaction system (i.e., a three-necked flask, the same below) and allowed to react for 1 minute. The temperature was raised to 310°C, and 20 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was quickly added. When the temperature reached 310°C again, 5 mL of selenium-trioctylphosphine (Se-TOP, 2 mol / L) was added dropwise at a rate of 5 mL / h using a syringe pump. When half of the selenium-trioctylphosphine had been added, 10 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was quickly added to the reaction system to form a ZnSe transition layer, resulting in a ZnSeTe / ZnSe core-shell structure.

[0105] After the addition of selenium-trioctylphosphine was completed, 10 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was quickly added to the reaction system; the temperature was raised to 330°C, and 4 mL of sulfur-trioctylphosphine (S-TOP, 2 mol / L) was added dropwise at a rate of 8 mL / h using a syringe pump; when half of the sulfur-trioctylphosphine was added, 10 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was quickly added to the reaction system to form ZnSe 1-x S x Transition layer, obtain ZnSeTe / ZnSe / ZnSe 1-x S x Core-shell structure.

[0106] Step S3: Preparation of ZnS outer shell

[0107] After the above-mentioned sulfur-trioctylphosphine was added dropwise, the temperature was lowered to 250°C, and 24 mL of zinc oleylamine (Zn / OlAm, 0.4 mol / L) was added dropwise to the reaction system at a rate of 24 mL / h using a syringe pump. At the same time, 6 mL of sulfur-trioctylphosphine (S-TOP, 2 mol / L) was added dropwise to the reaction system at a rate of 6 mL / h using a syringe pump.

[0108] Maintaining 250°C, 8 mL of zinc oleylamine (Zn / OlAm, 0.4 mol / L) was added dropwise to the reaction system at a rate of 24 mL / h using a syringe pump. At the same time, 1 mL of n-dodecyl mercaptan (DDT) was added dropwise to the reaction system at a rate of 3 mL / h using a syringe pump. After the reaction was completed, heating was stopped and the reaction solution was allowed to cool to room temperature. A ZnS shell layer was formed to obtain ZnSeTe / ZnSe / ZnSe 1-x S x / ZnS core-shell structure, that is, blue light ZnSeTe core-shell quantum dots.

[0109] Example 2:

[0110] Step S1: Preparation of nuclear bodies

[0111] To a 250mL three-necked flask, 1.02g of palmitic acid (PA, 4mmol / L), 5mL of oleylamine (OlAm), and 20mL of trioctylamine (TOA) were rapidly added. The mixture was evacuated and heated to 120°C, where it was maintained in vacuum for 2h. Ar was introduced, the reaction temperature was set to 240°C, and the temperature was increased. Once the temperature reached 240°C, 1mL of diphenylphosphine (DPP), 0.5mL of selenium-trioctylphosphine (Se-TOP, 2mol / L), and 0.5mL of tellurium-trioctylphosphine (Te-TOP, 0.1mol / L) were rapidly injected, followed by a 5min reaction. Then, 2.5mL of diethylzinc (DEZ, 1mol / L) was rapidly injected and the reaction continued for 25min, forming blue-emitting ZnSeTe cores.

[0112] Step S2: Preparation of ZnSe transition layer and ZnSe 1-x S x transition layer

[0113] To the reaction system (i.e., a three-necked flask, the same below), 0.15 mL of hydrofluoric acid-acetone solution (HF-acetone, 10% HF, 90% acetone) was rapidly added and allowed to react for 1 minute. The temperature was raised to 310°C, and 20 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was rapidly added. When the temperature reached 310°C again, 5 mL of selenium-trioctylphosphine (Se-TOP, 2 mol / L) was added dropwise at a rate of 6 mL / h using a syringe pump. When half of the selenium-trioctylphosphine had been added, 10 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was rapidly added to the reaction system to form a ZnSe transition layer, resulting in a ZnSeTe / ZnSe core-shell structure.

[0114] After the addition of selenium-trioctylphosphine was completed, 10 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was quickly added to the reaction system; the temperature was raised to 330°C, and 4 mL of sulfur-trioctylphosphine (S-TOP, 2 mol / L) was added dropwise at a rate of 9 mL / h using a syringe pump; when half of the sulfur-trioctylphosphine was added, 10 mL of zinc oleate (Zn(OA)2, 0.71 mol / L) was quickly added to the reaction system to form ZnSe 1-x S x Transition layer, obtain ZnSeTe / ZnSe / ZnSe 1-x S x Core-shell structure.

[0115] Step S3: Preparation of ZnS outer shell

[0116] After the above-mentioned sulfur-trioctylphosphine was added dropwise, the temperature was lowered to 250°C, and 24 mL of zinc oleylamine (Zn / OlAm, 0.4 mol / L) was added dropwise to the reaction system at a rate of 22 mL / h using a syringe pump. At the same time, 6 mL of sulfur-trioctylphosphine (S-TOP, 2 mol / L) was added dropwise to the reaction system at a rate of 8 mL / h using a syringe pump.

[0117] Maintaining 250°C, 8 mL of zinc oleylamine (Zn / OlAm, 0.4 mol / L) was added dropwise to the reaction system at a rate of 24 mL / h using a syringe pump. At the same time, 1 mL of n-dodecyl mercaptan (DDT) was added dropwise to the reaction system at a rate of 3 mL / h using a syringe pump. After the reaction was completed, heating was stopped and the reaction solution was allowed to cool to room temperature. A ZnS shell layer was formed to obtain ZnSeTe / ZnSe / ZnSe 1-x S x / ZnS core-shell structure, that is, blue light ZnSeTe core-shell quantum dots.

[0118] Comparative Example 1:

[0119] Step S1: Preparation of blue-light ZnSeTe core

[0120] In a 300 milliliter (mL) reaction flask, zinc acetate and palmitic acid were dissolved in trioctylamine and heated at 120°C under vacuum. After one hour, the atmosphere in the flask was replaced with an inert gas (nitrogen), and the reaction flask was heated to 300°C. Selenium-trioctylphosphine (Se-TOP, 2mol / L) and tellurium-trioctylphosphine (Te-TOP, 0.5mol / L) were rapidly injected into the flask, and the reaction was carried out for 60 minutes. The molar ratio between the zinc precursor and the selenium precursor was 2: 1 (Zn: Se), and the molar ratio between the tellurium precursor and the selenium precursor was 0.07: 1 (Te: Se). The reactor was cooled to room temperature and acetone was added to promote the formation of a precipitate, which was centrifuged to obtain a blue ZnSeTe nucleus, which was then dispersed in toluene.

[0121] Step S2: Preparation of ZnSe transition layer

[0122] To a 300 mL reaction flask, trioctylamine (TOA), zinc acetate and oleic acid were added, and the mixture was vacuum treated at 120 ° C for one hour, and the atmosphere in the flask was replaced with an inert atmosphere (nitrogen). When the flask was heated to a temperature of 300 ° C, the blue light ZnSeTe core was quickly added, followed by selenium-trioctylphosphine (Se-TOP, 2 mol / L), and the reaction was carried out for 120 minutes. Wherein, the molar ratio between the zinc precursor and the selenium precursor was about 2.85: 1.5. The flask was cooled to room temperature, and acetone was added to promote the formation of a precipitate, and separated via centrifugation to obtain a ZnTeSe / ZnSe core-shell structure, which was then dispersed in toluene.

[0123] Step S3: Preparation of ZnS outer shell

[0124] To a 300 mL reaction flask, trioctylamine (TOA), zinc acetate and oleic acid were added, and the mixture was vacuum treated at 120 ° C for one hour, and the atmosphere in the flask was replaced with nitrogen. The flask was cooled to 250 ° C, and the ZnTeSe / ZnSe core-shell structure was quickly added, followed by sulfur-trioctylphosphine (S-TOP, mol / L) and reacted for 60 minutes. The molar ratio between the zinc precursor and the sulfur precursor was 2: 1. The flask was cooled to room temperature, and acetone was added to promote the formation of a precipitate, and the ZnTeSe / ZnSe / ZnS core-shell structure, i.e., blue light ZnSeTe core-shell quantum dots, was obtained by centrifugation.

[0125] As can be seen from Examples 1-2, when synthesizing the blue-light ZnSeTe core body in the present application, an activity enhancer is added to improve the reactivity of the selenium precursor and the tellurium precursor, and the distribution of Se and Te in the ZnSeTe core body is more uniform. On this basis, the mass ratio of the added selenium precursor, tellurium precursor and zinc precursor is controlled, so that the selenium precursor, tellurium precursor and zinc precursor are almost completely reacted while the ZnSeTe core body emits blue light, and there is no need for purification and extraction steps, thereby greatly simplifying the synthesis steps. In Comparative Example 1, after each step, purification and extraction steps must be performed, and then the oily ligand and organic solvent are re-added, vacuum is drawn, and the temperature is raised; the process is cumbersome and the synthesis time is long.

[0126] Photoluminescence (PL) performance:

[0127] The blue light ZnSeTe core-shell quantum dots of Examples 1-2 and Comparative Example 1 were respectively measured for their photoinduced maximum emission peak wavelength and half-maximum width (FWHM) using a Hatichi F4500 fluorescence spectrophotometer, and their quantum efficiency (QY) was respectively measured using a fluorescence quantum efficiency meter. The test results are shown in Table 1.

[0128] Table 1: Photoluminescence performance test results of Examples and Comparative Examples.

[0129] As can be seen from Table 1, the blue light ZnSeTe core-shell quantum dots of Example 1-2 have a narrow emission linewidth (the maximum photoinduced emission peak wavelength is 450±5nm); the blue light ZnSeTe core-shell quantum dots have uniform particle size, and the FWHM value is significantly lower than that of Comparative Example 1; and the quantum efficiency QY is significantly better than that of Comparative Example 1.

[0130] Electroluminescence (EL) performance:

[0131] The blue ZnSeTe core-shell quantum dots of Examples 1-2 and Comparative Example 1 were used to prepare electroluminescent devices, respectively, in the following steps:

[0132] The blue light ZnSeTe core-shell quantum dots are mixed with a photoresist and spin-coated to form a blue light ZnSeTe light-emitting layer;

[0133] Providing a flexible substrate on which an ITO conductive layer is formed;

[0134] The PEDOT:PSS layer, PF8 layer, and blue light emitting ZnSeTe layer were spin-coated on the ITO conductive layer in sequence;

[0135] A ZnO electron transport layer was spin-coated on the blue light emitting ZnSeTe layer;

[0136] An Al layer is evaporated on the ZnO electron transport layer;

[0137] The electroluminescent device is encapsulated by using encapsulation glue.

[0138] The electroluminescent devices prepared in Examples 1-2 and Comparative Example 1 were tested using a Spectra Scan PR-655 instrument for the maximum emission peak wavelength, full width at half maximum (FWHM), maximum external quantum efficiency at 2000 nits (EQE@2000nits), current efficiency at 2000 nits (CE@2000nits), luminance at 4 V (L@4V), and current density at 4 V (J@4V). The test results are shown in Table 2.

[0139] Table 2: Electroluminescence performance test results of Examples and Comparative Examples.

[0140] As can be seen from Table 2, the blue light ZnSeTe core-shell quantum dots of Examples 1-2 have a narrow emission linewidth (the maximum photoinduced emission peak wavelength is 450±5 nm); the blue light ZnSeTe core-shell quantum dots have uniform particle size, and the FWHM value is significantly lower than that of Comparative Example 1; and the electroluminescent properties such as maximum external quantum efficiency EQE and brightness are significantly better than those of Comparative Example 1.

[0141] Although this application has disclosed various aspects and embodiments, other aspects and embodiments will be readily apparent to those skilled in the art. Variations and modifications may be made without departing from the spirit of this application, and all such variations and modifications are within the scope of this application. The various aspects and embodiments disclosed in this application are provided for illustrative purposes only and are not intended to limit this application. The actual scope of this application is determined by the claims.

Claims

1. A preparation method of blue-light ZnSeTe core-shell quantum dots, characterized in that, The preparation method includes the steps: S1. Prepare the core: At 220 - 260 °C, add an activity enhancer, a selenium precursor, a tellurium precursor, and a zinc precursor and react them together to form a blue-light ZnSeTe core; S2. Prepare the transition layer: Add an etchant to S1 to etch the blue-light ZnSeTe core; after heating, add a zinc precursor and a selenium precursor, wherein the selenium precursor is added dropwise at a rate of 4 - 6 mL / h to form a ZnSe transition layer coating the blue-light ZnSeTe core; S3. Prepare the outer shell layer: After cooling, add a zinc precursor and a sulfur precursor to S2, and the zinc precursor is an amine-containing zinc precursor to form a ZnS outer shell layer coating the transition layer.

2. The preparation method of the blue light ZnSeTe core-shell quantum dots according to claim 1, characterized in that, In step S1, it includes one or more of the following features: (1) First add a fatty acid, an oily ligand, and an organic solvent, evacuate the air, introduce an inert gas for protection, and then heat to 220 - 260 °C; (2) The activity enhancer is used to enhance the reaction activity of the selenium precursor and the tellurium precursor, and the activity enhancer includes at least one of diphenylphosphine (DPP), triphenylphosphine, tributylphosphine (TBP), and tripentylphosphine; (3) The molar ratio of the added activity enhancer to the selenium precursor is (3 - 6):1; (4) The molar ratio of the added tellurium precursor, selenium precursor, and zinc precursor is 1:(20 - 30):(40 - 60); (5) At 220 - 260 °C, first add the activity enhancer, selenium precursor, and tellurium precursor, react for 3 - 7 min, and then add the zinc precursor and react for 20 - 30 min to form a blue-light ZnSeTe core; (6) The diameter of the blue-light ZnSeTe core is 4.1 - 4.5 nm.

3. The preparation method of the blue-light ZnSeTe core-shell quantum dots according to claim 1 or 2, characterized in that, In step S2, after heating to 300 - 330 °C, add the zinc precursor and the selenium precursor, and the molar ratio of the added selenium precursor to the zinc precursor is 1:(1.5 - 4); Preferably, when the temperature reaches 300 - 330 °C, add 2 / 5 - 4 / 5 of the zinc precursor, then add the selenium precursor dropwise at a rate of 4 - 6 mL / h, and when half of the selenium precursor has been added dropwise, add the remaining zinc precursor; Preferably, the thickness of the ZnSe transition layer is 2.4 - 2.6 nm.

4. The preparation method of the blue light ZnSeTe core-shell quantum dots according to any one of claims 1-3, characterized in that, In step S2, after forming the ZnSe transition layer, the temperature is raised to 320 - 340 °C, and a zinc precursor and a sulfur precursor are added to form ZnSe coating the ZnSe transition layer 1-x S x transition layer, 0 < X < 1; wherein, the molar ratio of the sulfur precursor to the zinc precursor added is 1:(1.5 - 4), and the sulfur precursor is added dropwise at a rate of 6 - 10 mL / h; Preferably, when the temperature reaches 310 - 340 °C, add 2 / 5 - 4 / 5 of the zinc precursor, then add the sulfur precursor dropwise at a rate of 6 - 10 mL / h, and when half of the sulfur precursor has been added dropwise, add the remaining zinc precursor; Preferably, the ZnSe 1-x S x The thickness of the transition layer is 0.25 - 0.35 nm.

5. The preparation method of the blue-light ZnSeTe core-shell quantum dots according to any one of claims 1-4, characterized in that, In step S3, after cooling to 240 - 290 °C, add the amine-containing zinc precursor and the sulfur precursor, add the amine-containing zinc precursor dropwise at a rate of 22 - 26 mL / h, and at the same time add the sulfur precursor dropwise at a rate of 4 - 8 mL / h to form a ZnS outer shell layer; Preferably, the molar ratio of the added sulfur precursor to the amine-containing zinc precursor is 1:(0.8 - 3).

6. The preparation method of the blue-light ZnSeTe core-shell quantum dots according to any one of claims 1-5, characterized in that, The preparation method further includes the step: S4. Add the amine-containing zinc precursor and a thiol ligand to step S3 to increase the thickness of the ZnS outer shell layer; Preferably, in step S4, add the amine-containing zinc precursor dropwise at a rate of 22 - 26 mL / h, and at the same time add the thiol ligand dropwise at a rate of 2 - 5 mL / h; Preferably, the molar ratio of the thiol ligand to the amine-containing zinc precursor added is 1:(0.8 - 3); Preferably, the thickness of the ZnS outer shell layer is 0.7 - 0.9 nm.

7. The preparation method of the blue light ZnSeTe core-shell quantum dots according to any one of claims 1-6, characterized in that, The maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 440 - 460 nm; Preferably, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 445 - 455 nm; Preferably, the blue light ZnSeTe core-shell quantum dots are cube-like or tetrahedron-like.

8. A blue-light ZnSeTe core-shell quantum dot, characterized in that, The blue light ZnSeTe core-shell quantum dots are obtained by the preparation method according to any one of claims 1 - 7.

9. The blue-light ZnSeTe core-shell quantum dots according to claim 8, wherein, The diameter of the blue light ZnSeTe core is 4.1 - 4.5 nm, the thickness of the ZnSe transition layer is 2.4 - 2.6 nm, and the ZnSe 1-x S x transition layer has a thickness of 0.25 - 0.35 nm, and the ZnS outer shell layer has a thickness of 0.7 - 0.9 nm; Preferably, the maximum emission peak wavelength of the blue light ZnSeTe core-shell quantum dots is 440 - 460 nm; Preferably, the blue light ZnSeTe core-shell quantum dots are cube-like or tetrahedron-like.

10. A display device, characterized in that, The display device includes the blue light ZnSeTe core-shell quantum dots according to any one of claims 8 - 9.

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