An application of CsPbBr3@SiO2 perovskite quantum dots
By forming a discontinuous SiO2 shell on the surface of perovskite quantum dots, the balance between the stability of perovskite quantum dots and sensing detection was solved, enabling efficient detection of Cu2+ and Hg2+.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGZHOU UNIV
- Filing Date
- 2023-03-16
- Publication Date
- 2026-04-21
AI Technical Summary
Existing perovskite quantum dots are susceptible to fluorescence quenching due to external environmental factors, and the shell's ability to improve stability hinders communication with the outside world, affecting sensing and optoelectronic device applications.
CsPbBr3@SiO2 perovskite quantum dots were synthesized by hot injection method, and a discontinuous SiO2 shell was formed by centrifugation and washing to enhance stability while retaining the connection with the outside world.
It achieves improved stability of perovskite quantum dots, while also enabling efficient detection of Cu2+ and Hg2+ in water, exhibiting good selectivity and anti-interference capabilities.
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Figure CN116359188B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of water quality testing technology, specifically relating to the application of CsPbBr3@SiO2 perovskite quantum dots. Background Technology
[0002] With rapid industrial development, heavy metal ions in industrial wastewater pose a serious threat to organisms and the environment due to their environmental toxicity, non-biodegradability, and persistence. In the environmental and health field, heavy metals mainly refer to elements with significant biotoxicity such as arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and mercury (Hg), and also broadly refer to common heavy metals such as nickel (Ni), copper (Cu), manganese (Mn), and zinc (Zn). Therefore, developing methods for detecting and removing toxic heavy metal ions is a hot research topic in this field.
[0003] Heavy metal ion detection technologies are mainly divided into three categories: optical detection technology, spectroscopic detection technology, and electrochemical detection technology. While spectroscopic methods offer high sensitivity, they are expensive, involve complex processing, and are more suited to laboratory experiments. Electrochemical detection methods offer high sensitivity, simple equipment, and fast analysis speed, but are susceptible to interference from other ions, exhibit overlapping peaks, and have easily corroded electrodes. Fluorescence analysis, which modifies the physicochemical properties of fluorescent materials by the analyte, offers advantages such as high sensitivity, strong selectivity, and ease of use. With appropriate fluorescent materials, target analytes can be detected quickly and accurately with strong anti-interference capabilities, making it a promising area for environmental monitoring and capable of detecting multiple ions in water. Perovskite nanocrystals are considered the most promising fluorescent probes due to their tunable fluorescence emission wavelength, high photoluminescence quantum yield (PLQY), and narrow full width at half maximum (FWHM).
[0004] Perovskite quantum dots (PDOs) are highly susceptible to fluorescence quenching due to environmental factors such as water and oxygen. To address this issue, many studies have employed coating methods to form thicker and denser shells on the surface of PDOs, thereby enhancing their stability. While these shells improve stability, and some even allow PDOs to remain stable in water for extended periods, they also hinder the interaction between PDOs and their external environment (such as carrier migration), negatively impacting their applications in sensing and optoelectronic devices. Therefore, researching novel surface shells for PDOs to achieve a balance between stability and interaction with their external environment is of great significance. Summary of the Invention
[0005] To overcome the defects and shortcomings of the existing technology, the present invention aims to provide an application of CsPbBr3@SiO2 perovskite quantum dots. Perovskite quantum dots are synthesized using a hot-injection method. Subsequently, the quantum dots are collected by centrifugation and washed with a mixed solvent of n-hexane and ethyl acetate to remove some of the ligands on the surface of the quantum dots. Finally, the silicon-containing ligands on the surface of the quantum dots are hydrolyzed, resulting in a thin, discontinuous SiO2 shell coating on the surface of the quantum dots. This achieves both improved stability of the perovskite quantum dots and efficient detection of copper and mercury ions.
[0006] According to the present invention, an application of CsPbBr3@SiO2 perovskite quantum dots is used for the detection of Cu in water. 2+ or Hg 2+ The method for preparing the perovskite quantum dots includes:
[0007] S1 Preparation of cesium oleate solution: Cesium carbonate (Cs2CO3), oleic acid (OA) and 1-octadecene (ODE) are mixed, heated and stirred and vacuumed until the cesium carbonate is completely dissolved to obtain solution A;
[0008] S2 Preparation of APTES-PbBr2 solution: Lead bromide (PbBr2), oleylamine (OAm), oleic acid (OA), 3-aminopropyltriethoxysilane (APTES), and 1-octadecene (ODE) are mixed, heated and stirred under vacuum until the lead bromide is completely dissolved to obtain solution B;
[0009] Preparation of CsPbBr3@SiO2 quantum dots using S3:
[0010] S3.1 The solution A is thermally injected into the solution B to obtain solution C; immediately after the thermal injection, solution C is placed in an ice-water bath to cool to room temperature to obtain reaction solution I;
[0011] S3.2 The reaction solution I was washed by centrifugation with ethyl acetate to remove the supernatant and obtain precipitate I;
[0012] S3.3 Add a mixed solvent of n-hexane and ethyl acetate to the precipitate I, wash the precipitate I and quickly remove the solvent; repeat 2 to 3 times to obtain precipitate II;
[0013] S3.4 Add ethyl acetate to the precipitate II, let stand for 3-15 min to hydrolyze the silicon-containing ligand APTES on the surface of the quantum dots, discard the supernatant to obtain precipitate III;
[0014] S3.5 Disperse the precipitate III in n-hexane, centrifuge to remove large particles, and take the supernatant, which is the dispersion of CsPbBr3@SiO2.
[0015] Optionally, in step S1, the amount of Cs2CO3 used is related to the amount of OA used in the ratio of 1 mmol to (1-2) mL; the amount of Cs2CO3 used is related to the amount of ODE used in the ratio of 1 mmol to (16-25) mL.
[0016] Optionally, in step S2, the final concentration of PbBr2 is (0.03-0.05) mol / L, and the volume ratio of OAm, OA, APTES, and ODE is (1-2):3:3:30.
[0017] Optionally, in step S1, the heating temperature range is 140℃~200℃.
[0018] Optionally, in step S2, the heating temperature range is 120℃~190℃.
[0019] Optionally, in step S3.1, the temperature range of the heat injection is 140℃~200℃.
[0020] Optionally, the molar ratio of Cs2CO3 in step S1 to the molar ratio of PbBr2 in step S2 is 1:(0.2 to 0.4).
[0021] Optionally, in step S3, the centrifugation speed is 3000 rpm to 14000 rpm, and the centrifugation time is 3 min to 30 min.
[0022] The present invention has at least the following beneficial effects:
[0023] This application presents an application of CsPbBr3@SiO2 perovskite quantum dots for the detection of Cu in water. 2 + or Hg 2+ The method for preparing the perovskite quantum dots includes:
[0024] S1 Preparation of cesium oleate solution: Cesium carbonate (Cs2CO3), oleic acid (OA) and 1-octadecene (ODE) are mixed, heated and stirred and vacuumed until the cesium carbonate is completely dissolved to obtain solution A;
[0025] S2 Preparation of APTES-PbBr2 solution: Lead bromide (PbBr2), oleylamine (OAm), oleic acid (OA), 3-aminopropyltriethoxysilane (APTES), and 1-octadecene (ODE) are mixed, heated and stirred under vacuum until the lead bromide is completely dissolved to obtain solution B;
[0026] Preparation of CsPbBr3@SiO2 quantum dots using S3:
[0027] S3.1 The solution A is thermally injected into the solution B to obtain solution C; immediately after the thermal injection, solution C is placed in an ice-water bath to cool to room temperature to obtain reaction solution I;
[0028] S3.2 The reaction solution I was washed by centrifugation with ethyl acetate to remove the supernatant and obtain precipitate I;
[0029] S3.3 Add a mixed solution of n-hexane and ethyl acetate to the precipitate I, wash the precipitate I quickly and remove the supernatant; repeat 2 to 3 times to obtain precipitate II;
[0030] S3.4 Add ethyl acetate to the precipitate II, let stand for 3-15 min to hydrolyze the silicon-containing ligand APTES on the surface of the quantum dots, discard the supernatant to obtain precipitate III;
[0031] S3.5 Disperse the precipitate III in n-hexane, centrifuge to remove large particles, and take the supernatant, which is the dispersion of CsPbBr3@SiO2.
[0032] That is, perovskite quantum dots are synthesized using three types of ligands, and the perovskite quantum dots are cleaned using a mixed solvent of n-hexane and ethyl acetate to wash away some of the ligands, so that APTES are discontinuously dispersed on the surface of the perovskite quantum dots.
[0033] A discontinuous and non-uniform SiO2 shell was obtained on the surface of perovskite quantum dots, which not only improves the stability of perovskite quantum dots, but also enables perovskite quantum dots to efficiently detect copper or mercury ions in water. Attached Figure Description
[0034] Figure 1 A schematic diagram illustrating the formation principle of the CsPbBr3@SiO2 perovskite quantum dot core-shell structure, provided as an exemplary embodiment of the present invention;
[0035] Figure 2 XRD pattern of CsPbBr3@SiO2 prepared according to Exemplary Example 1 of the present invention;
[0036] Figure 3 TEM image of the CsPbBr3@SiO2 core-shell structure prepared for exemplary embodiment 1 of the present invention;
[0037] Figure 4 The CsPbBr3@SiO2 and Cu prepared in Exemplary Example 1 of the present invention 2+ The ratio of fluorescence intensity before and after the reaction with Cu 2+ A line graph showing the concentration change;
[0038] Figure 5 For the detection of Cu in exemplary embodiment 1 of the present invention2+ Bar chart showing the effect of different metal ions on the fluorescence intensity of CsPbBr3@SiO2 dispersion;
[0039] Figure 6 The CsPbBr3@SiO2 and Hg prepared in Exemplary Example 1 of the present invention 2+ A line graph showing the ratio of fluorescence intensity before and after the reaction as a function of mercury ion concentration;
[0040] Figure 7 For the detection of Hg in exemplary embodiment 1 of the present invention 2+ Bar chart showing the effect of different metal ions on the fluorescence intensity of CsPbBr3@SiO2 dispersion. Detailed Implementation
[0041] This invention is not limited to the following specific embodiments. Those skilled in the art can implement this invention using other specific embodiments based on the content disclosed herein. Any simple changes or modifications made to the design structure and concept of this invention fall within the protection scope of this invention.
[0042] Unless otherwise specified, all reagents used in the specific embodiments of this invention can be purchased commercially.
[0043] In a specific embodiment of the present invention, CsPbBr3@SiO2 perovskite quantum dots are used to detect copper ions and mercury ions using the following method:
[0044] CsPbBr3@SiO2 perovskite quantum dots were used to detect copper ions: 100 mL of 1 μM copper nitrate solution and 100 mL of 10 μM solutions of silver nitrate, cesium nitrate, zinc nitrate, aluminum nitrate, potassium nitrate, and sodium nitrate (all aqueous solutions) were prepared and placed in transparent glass bottles. 1 mL of the CsPbBr3@SiO2 dispersion prepared in step 3) was added. After addition, the yellow-green CsPbBr3@SiO2 and the aqueous solution of metal ions were clearly separated into layers. The mixed solution was stirred at 500 rpm for 5 min. Then, the upper layer of CsPbBr3@SiO2 solution was aspirated with a dropper and placed in a centrifuge tube for fluorescence intensity measurement.
[0045] CsPbBr3@SiO2 perovskite quantum dots were used to detect mercury ions: 100 mL of 1 μM mercuric nitrate solution and 100 mL of 10 μM solutions of silver nitrate, cesium nitrate, zinc nitrate, aluminum nitrate, potassium nitrate, and sodium nitrate (all aqueous solutions) were prepared. 1 mL of each solution was placed in a transparent glass bottle, and 1 mL of the CsPbBr3@SiO2 dispersion prepared in step 3) was added. After addition, the yellow-green CsPbBr3@SiO2 and the aqueous solution of metal ions were clearly separated into layers. The mixed solution was stirred at 500 rpm for 1 min, and then the upper layer of CsPbBr3@SiO2 solution was aspirated with a dropper and placed in a centrifuge tube for fluorescence intensity measurement.
[0046] The following detailed description is provided with reference to specific embodiments:
[0047] Example 1
[0048] S1 Weigh 0.814 g (2.5 mmol) of Cs2CO3 and place it in a 250 mL three-necked flask. Add 2.5 mL of OA and 40 mL of LODE, heat and stir to 120 °C, evacuate for 1 h, and after evacuation, introduce argon gas and heat to 150 °C until Cs2CO3 is completely dissolved to obtain a cesium oleate solution.
[0049] S2 Weigh 0.207 g (0.56 mmol) of PbBr2 and place it in another 250 mL three-necked flask. Add 1.5 mL OA, 1.5 mL APTES, 0.5 mL OAm and 15 mL ODE. Heat and stir to 120 °C, evacuate for 1 h. After evacuation, introduce argon gas and heat to 170 °C until PbBr2 is completely dissolved to obtain a PbBr2 solution.
[0050] Preparation of CsPbBr3@SiO2 quantum dots using S3:
[0051] S3.1 Take 1.2 mL of cesium oleate solution and inject it into PbBr2 solution. After reacting for 20 s, place it in an ice-water bath to cool to room temperature to obtain reaction solution I;
[0052] S3.2 Reaction solution I was placed in a centrifuge tube, and an equal volume of ethyl acetate was added. The tube was centrifuged at 10,000 rpm for 10 min. The supernatant was removed, and the precipitate was quickly washed once with 12 mL of a 1:1 mixture of n-hexane and ethyl acetate to remove some ligands. Then, 8 mL of ethyl acetate was added to the solution, and the mixture was allowed to stand for 15 min to allow the silicon-containing ligands APTES on the quantum dot surface to hydrolyze. Since the perovskite quantum dot surface contains three types of ligands, and some ligands are washed away from the quantum dots, the hydrolysis of APTES dispersed on the quantum dot surface will form a very thin, discontinuous shell. Finally, the precipitate was dispersed in n-hexane and centrifuged at 3000 rpm for 5 min to remove large particles. The supernatant was retained to obtain a dispersion of CsPbBr3@SiO2 perovskite quantum dots.
[0053] like Figure 2 , Figure 3 As shown, Figure 2 The diffraction peaks of CsPbBr3 and CsPbBr3 correspond to the standard colorimetric card, proving the synthesis of cubic phase CsPbBr3. The addition of APTES did not change the crystal structure of CsPbBr3. SiO2 is an amorphous amorphous material, so it is not shown on the XRD pattern. Figure 3 The TEM image shows the cubic phase structure of CsPbBr3 and a very thin, non-uniform SiO2 shell covering the CsPbBr3. For example... Figure 4 , Figure 6 As shown, the final concentration of the obtained dispersion was measured and diluted to 0.6 mg / mL. It was then reacted with various metal ions, and the fluorescence intensity after the reaction was measured. The relationship between the ratio of fluorescence intensity before and after the reaction and the concentration was plotted. Figure 4 The result shows that I0 / I changes with Cu 2+ The concentration increases with increasing concentration, showing a linear relationship, with the lowest detectable concentration reaching 0.003 μmol / L. Figure 6 The display shows I0 / I as Hg... 2+ The fluorescence intensity increases linearly with the increase of ion concentration, with a minimum detectable concentration of 0.001 μmol / L. However, the fluorescence intensity of CsPbBr3@SiO2 decreases less after reacting with other metal ions. Figure 5 and 7 This indicates that Cu 2+ and Hg 2+ The detection has good specificity.
[0054] Example 2
[0055] S1 Weigh 0.814 g of Cs₂CO₃ and place it in a 250 mL three-necked flask. Add 5 mL of OA and 62.5 mL of ODE, heat and stir to 120 °C, and evacuate under vacuum for 1 hour. After evacuation, argon gas is introduced, and the temperature is raised to 150 °C until the Cs₂CO₃ is completely dissolved, yielding a cesium oleate solution.
[0056] S2 Weigh 0.349 g (0.95 mmol) of PbBr2 and place it in another 250 mL three-necked flask. Add 1.5 mL OA, 1.5 mL APTES, 1 mL OAm, and 15 mL ODE. Heat and stir to 120 °C and evacuate for 1 hour. After evacuation, argon gas is introduced and the temperature is raised to 170 °C until PbBr2 is completely dissolved to obtain a PbBr2 solution.
[0057] Preparation of CsPbBr3@SiO2 quantum dots using S3:
[0058] S3.1 Take 1.2 mL of the prepared cesium oleate precursor solution and inject it into PbBr2. After reacting for 20 s, place it in an ice-water bath to cool to room temperature to obtain reaction solution I.
[0059] S3.2 Reaction solution I was placed in a centrifuge tube, and an equal volume of ethyl acetate was added. The tube was then centrifuged at 10,000 rpm for 10 min. The supernatant was removed, and the precipitate was quickly washed once with 12 mL of a 1:1 mixture of n-hexane and ethyl acetate to remove some ligands. Then, 8 mL of ethyl acetate was added to the solution, and the mixture was allowed to stand for 15 min to allow the silicon-containing ligands APTES on the quantum dot surface to hydrolyze. Since the perovskite quantum dot surface contains three types of ligands, and some ligands are washed away from the quantum dots, the hydrolysis of APTES dispersed on the quantum dot surface will form a very thin, discontinuous shell. Finally, the precipitate was dispersed in n-hexane and centrifuged at 3000 rpm for 5 min to remove large particles, yielding a dispersion of CsPbBr3@SiO2 perovskite quantum dots. 2+ The lowest detectable concentration is 0.006 μmol / L, Hg 2+ The lowest detectable concentration is 0.002 μmol / L.
[0060] Example 3
[0061] S1 Weigh 0.814 g of Cs2CO3 and place it in a 250 mL three-necked flask. Add 4.5 mL of OA and 50 mL of ODE, heat and stir to 120 °C, and evacuate for 1 h. After evacuation, argon gas is introduced and the temperature is raised to 150 °C until Cs2CO3 is completely dissolved to obtain a cesium oleate solution.
[0062] S2 weighed 0.318 g of PbBr2 and placed it in another 250 mL three-necked flask. Added 1.5 mL OA, 1.5 mL APTES, 0.5 mL OAm, and 15 mL ODE. The mixture was heated and stirred to 120 °C and evacuated for 1 hour. After evacuation, argon gas was introduced, and the temperature was raised to 170 °C until PbBr2 was completely dissolved, yielding a PbBr2 solution.
[0063] Preparation of CsPbBr3@SiO2 quantum dots using S3:
[0064] S3.1 1.2 mL of the prepared cesium oleate precursor solution was injected into PbBr2. After reacting for 20 s, the solution was cooled to room temperature in an ice-water bath. An equal volume of ethyl acetate was added, followed by centrifugation at 10,000 rpm for 10 min. The supernatant was removed, and the precipitate was quickly washed once with 12 mL of a 2:1 mixture of n-hexane and ethyl acetate to remove some ligands. Ethyl acetate was then added to the solution, and the mixture was allowed to stand for 15 min. Another 8 mL of ethyl acetate was added, and the mixture was allowed to stand for another 15 min to hydrolyze the silicon-containing ligand APTES on the quantum dot surface. Finally, the precipitate was dispersed in n-hexane and centrifuged at 3000 rpm for 5 min to remove large particles, yielding a CsPbBr3@SiO2 dispersion. 2+ The lowest detectable concentration is 0.004 μmol / L, Hg 2+ The lowest detectable concentration is 0.003 μmol / L.
[0065] Example 4
[0066] S1 Weigh 0.814 g of Cs2CO3 and place it in a 250 mL three-necked flask. Add 4 mL of OA and 55 mL of ODE, heat and stir to 120 °C, and evacuate for 1 h. After evacuation, argon gas is introduced and the temperature is raised to 150 °C until Cs2CO3 is completely dissolved to obtain a cesium oleate solution.
[0067] S2 Weigh 0.3g of PbBr2 and place it in another 250mL three-necked flask. Add 1.5mL OA, 1.5mL APTES, 0.5mL OAm, and 15mL ODE. Heat and stir to 120℃ and evacuate for 1 hour. After evacuation, argon gas is introduced and the temperature is raised to 170℃ until PbBr2 is completely dissolved to obtain a PbBr2 solution.
[0068] Preparation of CsPbBr3@SiO2 quantum dots using S3:
[0069] S3.1 Take 1.2 mL of the prepared cesium oleate precursor solution and inject it into PbBr2. After reacting for 20 s, place it in an ice-water bath to cool to room temperature.
[0070] S3.2 Add an equal volume of ethyl acetate, then centrifuge at 10000 rpm for 10 min. Remove the supernatant. Quickly wash the precipitate twice with 12 mL of a 1:1 mixture of n-hexane and ethyl acetate to remove some ligands. Then add ethyl acetate to the solution and let it stand for 15 min. Add another 8 mL of ethyl acetate and let it stand for 15 min to hydrolyze the silicon-containing ligand APTES on the quantum dot surface, dispersing the precipitate in n-hexane. Centrifuge at 3000 rpm for 5 min to remove large particles, obtaining a dispersion of CsPbBr3. 2+ The lowest detectable concentration is 0.01 μmol / L, Hg 2+ The lowest detectable concentration is 0.007 μmol / L.
[0071] As can be seen from the specific embodiments and examples of the present invention, the CsPbBr3@SiO2 perovskite quantum dots obtained by the perovskite quantum dot preparation method provided in the specific embodiments of the present invention achieve a balance between the stability of perovskite quantum dots and their interaction with the outside world. That is, it can provide both the stability of perovskite quantum dots and the purpose of efficiently detecting copper ions and mercury ions.
[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, and their descriptions are relatively specific and detailed, but not intended to limit the scope of the invention. For those skilled in the art, various modifications and variations can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.
Claims
1. An application of CsPbBr3@SiO2 perovskite quantum dots, characterized in that, Used to detect Cu in water 2+ or Hg 2+ The method for preparing the perovskite quantum dots includes: S1 Preparation of cesium oleate solution: Cesium carbonate (Cs2CO3), oleic acid (OA) and 1-octadecene (ODE) are mixed, heated and stirred and vacuumed until the cesium carbonate is completely dissolved to obtain solution A; S2 Preparation of APTES-PbBr2 solution: Lead bromide (PbBr2), oleylamine (OAm), oleic acid (OA), 3-aminopropyltriethoxysilane (APTES), and 1-octadecene (ODE) are mixed, heated and stirred under vacuum until the lead bromide is completely dissolved to obtain solution B; Preparation of CsPbBr3@SiO2 quantum dots using S3: S3.1 The solution A is thermally injected into the solution B to obtain solution C; immediately after the thermal injection, solution C is placed in an ice-water bath to cool to room temperature to obtain reaction solution I; S3.2 The reaction solution I was washed by centrifugation with ethyl acetate to remove the supernatant and obtain precipitate I; S3.3 Add a mixed solvent of n-hexane and ethyl acetate to the precipitate I, wash the precipitate I and quickly remove the solvent; repeat 2 to 3 times to obtain precipitate II; S3.4 Add ethyl acetate to the precipitate II, let stand for 3-15 min to hydrolyze the silicon-containing ligand APTES on the surface of the quantum dots, discard the supernatant to obtain precipitate III; S3.5 Disperse the precipitate III in n-hexane, centrifuge to remove large particles, and take the supernatant, which is the dispersion of CsPbBr3@SiO2.
2. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, In step S1, The relationship between the amount of Cs2CO3 and the amount of OA is 1 mmol: (1-2) mL; The relationship between the amount of Cs2CO3 and the amount of ODE is 1 mmol: (16-25) mL.
3. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, In step S2, The final concentration of PbBr2 is (0.03~0.05) mol / L, and the volume ratio of OAm, OA, APTES and ODE is (1~2):3:3:
30.
4. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, In step S1, the heating temperature range is 140℃~200℃.
5. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, In step S2, the heating temperature range is 120℃~190℃.
6. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, In step S3.1, the temperature range of the heat injection is 140℃~200℃.
7. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, The molar ratio of Cs2CO3 in step S1 to the molar ratio of PbBr2 in step S2 is 1:(0.2~0.4).
8. The application of the CsPbBr3@SiO2 perovskite quantum dots as described in claim 1, characterized in that, In step S3, the centrifugation speed is 3000 rpm to 14000 rpm, and the centrifugation time is 3 min to 30 min.