Preparation method of core-shell quantum dots
The novel etching method for preparing InP-based core-shell quantum dots solves the problems of equipment wear and environmental pollution during the etching process, achieving efficient quantum dot production and improving the luminescence performance of quantum dots.
Patent Information
- Application Number
- CN202511530940.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-24
- Publication Date
- 2026-03-10
AI Technical Summary
In current InP-based quantum dot production, etching requires fluorine-containing compounds, which leads to equipment wear and environmental pollution, posing potential risks. Furthermore, the luminescence performance of quantum dots is not perfect.
A novel etching method was employed, in which a dispersion containing quantum dot cores was prepared and mixed with C14 to C18 fatty acid zinc and first sulfur precursors at 150–200 °C. Subsequently, a shell coating was performed at 250–340 °C, using selenium and zinc precursors to react and form InP-based core-shell quantum dots, thus avoiding the use of hydrofluoric acid.
The prepared InP-based core-shell quantum dots exhibit high quantum yield and narrow half-maximum width, avoiding the risks associated with hydrofluoric acid and improving the luminescence performance of the quantum dots.
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Abstract
Description
Technical Field
[0001] This application relates to the field of quantum dot synthesis technology, and more specifically, to an InP-based core-shell quantum dot and its preparation method. Background Technology
[0002] Quantum dots (QDs), as a novel nanomaterial for fluorescence, exhibit a strong correlation between their size and optical properties. Compared to traditional fluorescent materials, quantum dots possess a series of unique optical properties, including tunable spectra, narrow emission peak half-width, large Stokes shift, and high excitation efficiency. This allows for easy achievement of high color gamut (≥98% NTSC) packaging effects, attracting widespread attention from the LED backlight industry. However, the aforementioned luminescent properties of quantum dots are not yet perfect, especially the performance of cadmium-free quantum dots, which hinders the competitiveness of their downstream applications. Summary of the Invention
[0003] The purpose of this application is to provide an InP-based core-shell quantum dot and its preparation method. The aim is to solve the problems of equipment wear, environmental pollution and potential risks caused by the production of hydrofluoric acid during the etching process of existing InP-based quantum dot production, which requires fluorine-containing compounds.
[0004] To address the aforementioned problems, this application proposes a method for preparing core-shell quantum dots, the method comprising:
[0005] S1, prepare a dispersion of a first noncoordinate solvent containing quantum dot nuclei, wherein the quantum dot nuclei include phosphorus and indium.
[0006] S2, the dispersion, C 14 To C 18 The zinc fatty acid, the first sulfur precursor, and the second noncoordinate solvent are mixed in a container and reacted at 150–200 °C for a certain time to obtain an intermediate product system containing etched quantum dot cores.
[0007] S3: The etched quantum dot core is coated with a shell to obtain the core-shell quantum dot.
[0008] Optionally, S1 specifically includes: mixing an indium precursor, an optional first ligand, and a third non-coordination solvent to form a first mixture; adding a phosphorus precursor and an optional second ligand to the first mixture and reacting at 150–330°C for a certain time to obtain a second mixture containing quantum dot nuclei; separating and purifying the quantum dot nuclei from the second mixture, and redispersing the quantum dot nuclei in the first non-coordination solvent to obtain a dispersion of the quantum dot nuclei in the first non-coordination solvent.
[0009] Optionally, S3 specifically includes: raising the temperature of the intermediate product system to 250-340°C, adding anionic precursor and zinc precursor to a container once or multiple times, reacting for a certain time to obtain the core-shell quantum dots; the anionic precursor includes at least one of selenium precursor and second sulfur precursor.
[0010] Optionally, the mass ratio of the first sulfur precursor to the quantum dot nucleus is 1:5 to 1:1.
[0011] Optionally, the first sulfur precursor is selected from at least one of zinc sulfide, sodium sulfide, elemental sulfur, thiourea, or thioacetamide.
[0012] Optionally, the reaction time of S2 is 0.1h to 1h, and the reaction time of S3 is 2h to 4h.
[0013] Optionally, the first ligand is C 12 -C 18 One or more of the fatty acids, wherein the second ligand is selected from at least one of fatty amine ligands and alkylphosphine ligands.
[0014] Optionally, the molar ratio of the anionic element in the anionic precursor to the zinc element in the zinc precursor is 1:1 to 1:1.2.
[0015] Optionally, the reaction time for step S1 is 0.5 h to 2 h.
[0016] Optionally, the zinc precursor is C 10 -C 22 Zinc carboxylate.
[0017] Optionally, the selenium precursor is selected from one or more of selenium-trioctylphosphine solution, selenium-tributylphosphine solution, and selenium octadecene suspension.
[0018] Optionally, the second sulfur precursor is selected from one or more of sulfur-trioctylphosphine solution and sulfur-tributylphosphine solution.
[0019] The InP-based core-shell quantum dots prepared in this application have the characteristics of high quantum yield and narrow half-peak width, which can eliminate various potential risks and hazards caused by the production or use of hydrofluoric acid in actual production.
[0020] The implementation methods are described in more detail below with reference to specific embodiments. However, these are exemplary examples of the content of this application, and the content of this application is not limited thereto. Attached Figure Description
[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:
[0022] Figure 1 The ultraviolet-visible absorption spectrum of the InP quantum dot core obtained in Example 1 of this application is shown.
[0023] Figure 2 The fluorescence emission spectrum of the InP quantum dot core obtained in Example 1 of this application is shown.
[0024] Figure 3 The fluorescence emission spectrum of the etched InP quantum dot core obtained in Example 2 of this application is shown.
[0025] Figure 4 This is a TEM image of the InP / ZnSe quantum dots obtained in Example 1 of this application.
[0026] Figure 5 The fluorescence emission spectrum of the InP / ZnSe quantum dots obtained in Example 1 of this application is shown.
[0027] Figure 6 This is a TEM image of the InP / ZnSe quantum dots obtained in Comparative Example 2 of this application.
[0028] Figure 7 The fluorescence emission spectrum of the InP / ZnSe quantum dots obtained in Comparative Example 2 of this application is shown. Detailed Implementation
[0029] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0030] Existing InP-based quantum dot synthesis processes require an etching step to improve quantum dot fluorescence efficiency. However, regardless of whether inorganic fluorides such as ZnF2, organic fluorides, or HF are used, it is difficult to avoid the presence of hydrofluoric acid in the system during actual production—especially in large-scale production. Even with compliant equipment, pipelines, and harmless treatment methods for post-treatment of hydrofluoric acid, the inherent potential risks remain unavoidable.
[0031] We believe, and hereby propose, that the etching step can be viewed from two aspects, firstly H + The reaction with In-containing oxides can be considered microscopically as the stripping of the oxidized surface of the quantum dot core. Macroscopically, this manifests as a blue shift in the first exciton peak of the quantum dot core fluorescence, followed by the repair of defects in the quantum dot core by negative ions, thereby improving the efficiency of the quantum dot core. Based on this understanding, this application proposes a method for preparing core-shell quantum dots, the method comprising:
[0032] S1, a dispersion of the first noncoordinate solvent containing quantum dot nuclei, wherein the quantum dot nuclei include phosphorus and indium.
[0033] S2, dispersant, C 14 To C 18 The zinc fatty acid, the first sulfur precursor, and the second noncoordinate solvent are mixed in a container and reacted at 150–200 °C for a certain time to obtain an intermediate product system containing etched quantum dot cores.
[0034] S3: The etched quantum dot core is coated with a shell to obtain the core-shell quantum dot.
[0035] The above preparation method can eliminate various potential risks and hazards caused by the generation or use of hydrofluoric acid in actual production, and InP-based core-shell quantum dots have the characteristics of high quantum yield and narrow half-peak width.
[0036] The quantum dot cores mentioned above may also include at least one of other elements, such as Ga, Cd, Zn, Cu, Mg, Cl, F, I, and Se.
[0037] In some embodiments, S1 specifically includes: mixing an indium precursor, an optional first ligand, and a third non-coordination solvent to form a first mixture; adding a phosphorus precursor and an optional second ligand to the first mixture and reacting at 150–330°C for a certain time to obtain a second mixture containing quantum dot nuclei; separating and purifying the quantum dot nuclei from the second mixture, and redispersing the quantum dot nuclei in the first non-coordination solvent to obtain a dispersion of the first non-coordination solvent containing quantum dot nuclei.
[0038] In some embodiments, S3 specifically includes: raising the temperature of the intermediate product system to 250-340°C, adding anionic precursor and zinc precursor to a container once or multiple times, reacting for a certain time, and obtaining core-shell quantum dots; the anionic precursor includes at least one of selenium precursor and second sulfur precursor.
[0039] In some embodiments, precursors of other elements, such as at least one of Ga, Mg, Cu, and Cd precursors, may also be added to S3.
[0040] In some preferred embodiments, S3 specifically includes: raising the temperature of the intermediate product system to 250-340°C, adding selenium precursor and zinc precursor to a container, reacting for a certain time to obtain the first core-shell quantum dot; and continuing to add a second sulfur precursor and zinc precursor to the container, reacting for a certain time to obtain the second core-shell quantum dot.
[0041] In some embodiments, the anionic precursor and the zinc precursor in S3 are added independently by drop addition or injection or a combination thereof.
[0042] In some embodiments, the mass ratio of the first sulfur precursor to the quantum dot nucleus is 1:5 to 1:1.
[0043] In some embodiments, the first sulfur precursor is selected from at least one of zinc sulfide, sodium sulfide, elemental sulfur, thiourea, or thioacetamide.
[0044] In some embodiments, the molar ratio of the anionic element of the anionic precursor to the zinc element of the zinc precursor is 1:1 to 1:1.2.
[0045] In some embodiments, the reaction time of S2 is 0.1 h to 1 h, and the reaction time of S3 is 2 h to 4 h.
[0046] In some embodiments, the reaction time for step S1 is 0.5 h to 2 h.
[0047] In some embodiments, the zinc precursor is C 10 -C 22 The zinc carboxylate. In some embodiments, the zinc precursor is selected from one or more of zinc acetate, zinc stearate, zinc oleate, and zinc undecenoate.
[0048] In some embodiments, the selenium precursor is selected from one or more of selenium-trioctylphosphine solution, selenium-tributylphosphine solution, and selenium octadecene suspension.
[0049] In some embodiments, the second sulfur precursor is selected from one or more of sulfur-trioctylphosphine solution and sulfur-tributylphosphine solution.
[0050] In some embodiments, the first ligand is C 12- C 18 One or more of the fatty acids. Those skilled in the art will understand that when the indium precursor is a short-chain indium carboxylate or indium halide, C can be added. 12- C 18 Fatty acids act as the first ligand.
[0051] In some embodiments, the first noncoordination solvent and the second noncoordination solvent are independently selected from one or more of 1-octadecene, squalane, and petrolatum. In some embodiments, the third noncoordination solvent is selected from one or more of 1-octadecene, squalane, and petrolatum.
[0052] In some embodiments, the indium precursor is selected from one or more of indium chloride, indium tetradecanoate, indium oleate, and indium acetate. In some embodiments, the phosphorus precursor is selected from one or more of tris(trimethylsilyl)phosphine, tris(triethylsilyl)phosphine, and tris(dimethylamino)phosphine.
[0053] In some embodiments, the second ligand is selected from at least one of aliphatic amine ligands and alkylphosphine ligands.
[0054] In some embodiments, the aliphatic amine ligand is one or more of n-hexylamine, octylamine, dodecylamine, and dipropylamine, and the alkylphosphine ligand is selected from one or more of trioctylphosphine, tributylphosphine, and trihexylphosphine.
[0055] In some embodiments, the fluorescence peak wavelength of the prepared core-shell quantum dots is 550–650 nm. In some embodiments, the fluorescence peak wavelength of the prepared core-shell quantum dots is 620–640 nm.
[0056] In some embodiments, the core-shell quantum dots are InP / ZnSe / ZnS, and the fluorescence full width at half maximum (FWHM) is less than or equal to 40 nm. In some embodiments, the FWHM of the InP / ZnSe / ZnS quantum dots is greater than or equal to 38 nm.
[0057] In some embodiments, the fluorescence efficiency of InP / ZnSe / ZnS quantum dots is greater than or equal to 50%. In some embodiments, the fluorescence efficiency of InP / ZnSe / ZnS quantum dots is greater than or equal to 65%.
[0058] The implementation methods are described in more detail below with reference to specific embodiments. However, these are exemplary examples of the content of this application, and the content of this application is not limited thereto.
[0059] Preparation Example 1
[0060] Preparation of InP quantum dot cores
[0061] Weigh 0.093 g In(OAc)3 (indium acetate), 0.35 mL OA (oleic acid), and 16 g ODE (octadecene) into a 100 mL three-necked flask. Heat to 180 °C and exhaust for 2 h. Cool to 50 °C, add 0.8 mL TOA (trioctylamine) and 0.16 mL TMS-P (tris(trimethylsilyl)phosphine), and heat to 280 °C for 4 min. After cooling, purify with methanol / acetone and dilute to 4 OD / mL with n-hexane to obtain quantum dot nuclei with a first exciton peak of 593 nm and a half-peak width of 20.5 nm under UV fluorescence spectroscopy. The UV-Vis absorption spectrum is as follows: Figure 1 As shown, the fluorescence emission spectrum is as follows Figure 2 As shown.
[0062] Preparation Example 2
[0063] Etching of InP quantum dot cores
[0064] Add 0.5 g zinc sulfide, 0.1 mL OA, and 10 mL ODE to a 100 mL three-necked flask to prepare the InP core dispersion prepared in Example 1. After purging with nitrogen for 20 min, heat to 280 °C and etch for 20 min. After cooling, purify with methanol / acetone and dilute with n-hexane to 4 OD / mL. The fluorescence emission spectrum is shown below. Figure 3 As shown.
[0065] It should be noted that in Preparation Example 2, we separately illustrated the etching of InP quantum dot cores using oleic acid and zinc sulfide. The fluorescence emission spectra of the InP quantum dot cores (with the first exciton peak at 613 nm) are compared. Figure 2 The fluorescence emission spectrum after etching the same InP quantum dot core in Preparation Example 2 is shown. Figure 3 A clear blue shift can be visually observed in the first exciton peak at 607 nm. Based on this, we believe that such a comparison can illustrate the etching effect of this combination on the InP quantum dot core.
[0066] Example 1
[0067] In a 100 mL three-necked flask, 0.5 g of zinc sulfide (sulfur precursor: InP core = 5:1), 0.1 mL of OA, and 10 mL of ODE were added to prepare the InP core dispersion prepared in Example 1. Nitrogen gas was purged for 20 min, and the temperature was raised to 180 °C for etching for 20 min. The temperature was then raised to 280 °C, 1 mL of Se-TBP (1 M) was injected, and 2 g of Zn(OA)₂ was added. The reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) was injected, and 2 g of zinc oleate was added. The reaction was allowed to proceed for 1 h. The product system containing InP / ZnSe / ZnS was obtained by cooling. The product system was extracted three times with methanol to obtain the extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate obtained after centrifugation was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0068] Example 2
[0069] In a 100 mL three-necked flask, 0.3 g of sodium sulfide (sulfur precursor: InP core = 3:1), 0.1 mL of OA, and 10 mL of ODE were added to prepare the InP core dispersion prepared in Example 1. After purging with nitrogen for 20 min, the temperature was raised to 180 °C and etched for 20 min. The temperature was then raised to 280 °C, 1 mL of Se-TBP (1 M) was injected, and 2 g of Zn(OA)₂ was added. The reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) was injected, and 2 g of zinc stearate was added. The reaction was allowed to proceed for 1 h. The product system containing InP / ZnSe / ZnS was obtained by cooling. The product system was extracted three times with methanol to obtain the extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate obtained after centrifugation was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0070] Example 3
[0071] In a 100 mL three-necked flask, 0.4 g of thiourea (sulfur precursor: InP core = 4:1), 0.1 mL of OA, and 10 mL of ODE were added to prepare the InP core dispersion prepared in Example 1. After purging with nitrogen for 20 min, the temperature was raised to 180 °C and etched for 20 min. The temperature was then raised to 280 °C, 1 mL of Se-TBP (1 M) was injected, and 2 g of Zn(OA)2 was added. The reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) was injected, and 1.65 g of zinc myristate was added. The reaction was allowed to proceed for 1 h. The product system containing InP / ZnSe / ZnS was obtained by cooling. The product system was extracted three times with methanol to obtain the extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate obtained after centrifugation was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0072] Example 4
[0073] In a 100 mL three-necked flask, 0.4 g of thioacetamide (sulfur precursor: InP core = 4:1), 0.1 mL of OA, and 10 mL of ODE were added to prepare the InP core dispersion prepared in Example 1. Nitrogen gas was purged for 20 min, and the mixture was heated to 180 °C and etched for 20 min. The temperature was then raised to 280 °C, 1 mL of Se-TBP (1 M) was injected, and 2 g of Zn(OA)₂ was added. The reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) was injected, and 2 g of zinc oleate was added. The reaction was allowed to proceed for 1 h. The mixture was cooled to obtain a product system containing InP / ZnSe / ZnS. This product system was extracted three times with methanol to obtain an extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate obtained after centrifugation was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0074] Example 5
[0075] In a 100 mL three-necked flask, 0.1 g of sulfur powder (sulfur precursor: InP core = 1:1), 0.1 mL of OA, and 10 mL of ODE were added to prepare the InP core dispersion prepared in Example 1. After purging with nitrogen for 20 min, the temperature was raised to 180 °C and etched for 20 min. The temperature was then raised to 280 °C, 1 mL of Se-TBP (1 M) was injected, and 2 g of Zn(OA)2 was added. The reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) was injected, and 1.83 g of zinc palmitate was added. The reaction was allowed to proceed for 1 h. The product system containing InP / ZnSe / ZnS was obtained by cooling. The product system was extracted three times with methanol to obtain the extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate obtained after centrifugation was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0076] Comparative Example 1
[0077] To prepare the InP core dispersion prepared in Example 1, 10 mL of ODE was added to a 100 mL three-necked flask. After purging with nitrogen for 20 min, the temperature was raised to 280 °C, and 1 mL of Se-TBP (1 M) and 2 g of Zn(OA)2 were added. The reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) and 2 g of Zn(OA)2 were added, and the reaction was allowed to proceed for 1 h. After cooling, a product system containing InP / ZnSe / ZnS was obtained. The product system was extracted three times with methanol to obtain the extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate obtained after centrifugation was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0078] Comparative Example 2
[0079] To prepare the InP core dispersion prepared in Example 1, 0.5 g of zinc fluoride, 0.1 mL of OA, and 10 mL of ODE were added to a 100 mL three-necked flask. Nitrogen gas was purged for 20 min, and the mixture was heated to 180 °C and etched for 20 min. The temperature was then raised to 280 °C, 1 mL of Se-TBP (1 M) was injected, followed by 2 g of Zn(OA)₂, and the reaction was allowed to proceed for 1 h. Then, 1 mL of S-TBP (1 M) was injected, followed by 2 g of Zn(OA)₂, and the reaction was allowed to proceed for another 1 h. The mixture was then cooled to obtain a product system containing InP / ZnSe / ZnS. This product system was extracted three times with methanol to obtain an extract. The extract was precipitated with acetone, and the precipitate was centrifuged. The precipitate was then dissolved in n-hexane to obtain an InP / ZnSe / ZnS quantum dot hexane solution.
[0080] The InP / ZnSe / ZnS quantum dot hexane solutions (all 4 OD / mL) obtained in each embodiment and comparative example were tested using an integrating sphere, and the data are shown in Table 1 below.
[0081] Table 1
[0082] Fluorescence peak position / nm Fluorescence full width at half maximum (FWHM) / nm Quantum efficiency QY / % Example 1 629 39.2 68.3 Example 2 630 38.2 66.4 Example 3 631 40.1 62.7 Example 4 632 42.0 63.0 Example 5 638 45.1 62.4 Comparative Example 1 630 40.2 56.3 Comparative Example 2 630 41.0 65.4
[0083] In all embodiments, Example 1, using zinc sulfide, yielded the best results, with a half-width at 39.2 nm at the 629 nm peak position on PL and a QY of 68.3%, representing a significant improvement in QY compared to Comparative Example 1 without etching reagent. Compared to Comparative Example 2, which added zinc fluoride etching reagent, it exhibited a narrower emission half-width, but this application achieved similar results by avoiding the use of fluorides as etching agents.
[0084] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.
Claims
1. A method for preparing core-shell quantum dots, characterized in that, The preparation method comprises: S1, preparing a first non-coordinating solvent dispersion liquid containing quantum dot cores, wherein the quantum dot cores comprise phosphorus elements and indium elements; S2, the dispersion, C 14 To C 18 The zinc fatty acid, the first sulfur precursor, and the second noncoordinate solvent are mixed in a container and reacted at 150–200 °C for a certain time to obtain an intermediate product system containing etched quantum dot cores. S3, performing shell coating on the etched quantum dot cores to obtain the core-shell quantum dots.
2. The method for preparing core-shell quantum dots according to claim 1, characterized in that, The S1 specifically comprises: mixing an indium precursor, an optional first ligand and a third non-coordinating solvent to form a first mixed liquid; adding a phosphorus precursor and an optional second ligand into the first mixed liquid, and reacting at 150-330°C for a certain time to obtain a second mixed liquid containing quantum dot cores; separating and purifying the quantum dot cores from the second mixed liquid, and dispersing the quantum dot cores in a first non-coordinating solvent again to obtain the first non-coordinating solvent dispersion liquid containing quantum dot cores.
3. The method for preparing core-shell quantum dots according to claim 1, characterized in that, The S3 specifically comprises: increasing the temperature of the intermediate product system to 250-340°C, adding an anion precursor and a zinc precursor into the container one or more times, and reacting for a certain time to obtain the core-shell quantum dots; the anion precursor comprises at least one of a selenium precursor and a second sulfur precursor.
4. The method for preparing core-shell quantum dots according to claim 1, characterized in that, The mass ratio of the first sulfur precursor to the quantum dot cores is 1:5 to 1:
1.
5. The method for preparing core-shell quantum dots according to claim 1, characterized in that, The first sulfur precursor is selected from at least one of zinc sulfide, sodium sulfide, elemental sulfur, thiourea or thioacetamide.
6. The method for preparing core-shell quantum dots according to claim 1, characterized in that, The reaction time of the S2 is 0.1h to 1h, and the reaction time of the S3 is 2h to 4h.
7. The method of claim 2, wherein the first ligand is C 12- C 18 one or more of a fatty acid, and the second ligand is selected from at least one of a fatty amine ligand and an alkyl phosphine ligand.
8. The method for preparing core-shell quantum dots according to claim 3, characterized in that, The molar ratio of the anion element of the anion precursor to the zinc element of the zinc precursor is 1:1 to 1:1.
2.
9. The method for preparing core-shell quantum dots according to claim 3, characterized in that, The reaction time of the S1 step is from 0.5 h to 2 h; preferably, the zinc precursor is C 10 -C 22 zinc carboxylate of the formula 10. The method for preparing core-shell quantum dots according to claim 3, characterized in that, The selenium precursor is selected from one or more of selenium-trioctylphosphine solution, selenium-tributylphosphine solution and selenium octadecene suspension; preferably, the second sulfur precursor is selected from one or more of sulfur-trioctylphosphine solution and sulfur-tributylphosphine solution.