A lead halide perovskite quantum dot material, a preparation method therefor and applications thereof
The CsPbX3 quantum dots prepared by advanced ultrasonication and surfactant treatment solve the stability problem of lead halide perovskite quantum dots in polar environments, enabling rapid and sensitive detection of analytes in water, and are suitable for large-scale production.
Patent Information
- Application Number
- CN202610402834.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-23
AI Technical Summary
Lead halide perovskite quantum dots are structurally unstable in polar environments, making it impossible to achieve rapid and sensitive detection of analytes in water. Furthermore, existing modification methods are complex and difficult to scale up for production.
CsPbX3 quantum dots with high stability in polar environments were prepared by using advanced ultrasonic methods combined with surfactant treatment. The analytes in water were detected by fluorescence spectroscopy or colorimetric parameters.
Stable luminescence properties of CsPbX3 quantum dots in polar environments were achieved, simplifying the preparation process, making them suitable for large-scale production, and enabling rapid and sensitive detection of substances in water.
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Figure CN122255999A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of detection technology, specifically to a lead halide perovskite quantum dot material, its preparation method, and its applications. Background Technology
[0002] Lead halide perovskite CsPbX3 (X being Cl, Br, I, or a mixture of halogens) quantum dots have shown great application potential in optoelectronic devices such as solar cells, photodetectors, and light-emitting diodes in recent years due to their high defect tolerance, tunable emission gamut, simple synthesis methods, and excellent photoelectric properties. However, the practical application and promotion of these materials still face key technological bottlenecks.
[0003] On the one hand, CsPbX3 quantum dots have a typical ionic crystal structure, making them extremely sensitive to polar environments. Upon contact with water molecules, the ions on the surface of the quantum dots readily dissociate, causing the crystal structure to collapse rapidly, resulting in a sharp decline in fluorescence performance or even complete quenching. This inherent defect of poor water stability severely restricts the application of this type of material in aqueous systems, especially in detection fields involving aqueous environments such as biosensing and environmental monitoring. The instability of quantum dots in polar media has become a core obstacle hindering their practical application.
[0004] On the other hand, to improve the stability of CsPbX3 quantum dots, existing technologies mainly attempt to modify them through surface ligand engineering or inorganic shell coating. For example, long-chain organic ligand exchange strategies are used to replace the original oleic acid and oleylamine ligands with hydrophobic ligands, attempting to construct a hydrophobic barrier on the quantum dot surface; or wide-bandgap inorganic shells, such as the CsPbBr3@Cs4PbBr6 core-shell structure, are epitaxially grown to physically isolate and prevent water molecule erosion. However, these methods often suffer from complex processes, harsh reaction conditions, and difficulty in large-scale preparation. More importantly, excessive exchange of surface ligands may introduce new interface defects, leading to a decrease in the luminescence efficiency of the quantum dots; while inorganic shell coating usually requires high-temperature reaction conditions and it is difficult to precisely control the shell thickness. Incomplete coating or an excessively thick shell will affect the intrinsic optical properties of the quantum dots.
[0005] In the field of detection applications, the sensitive detection of substances such as halide ions, heavy metal ions, and organic pollutants in water is of great significance for environmental monitoring and food safety. Currently, the main detection methods for these substances include ion chromatography, atomic absorption spectrometry, and inductively coupled plasma mass spectrometry. While these methods offer high detection accuracy, they generally suffer from drawbacks such as expensive equipment, complex sample pretreatment, high operational expertise, and long detection cycles, making them unsuitable for rapid on-site detection. Fluorescence sensing-based detection methods have attracted widespread attention due to their ease of operation, rapid response, and high sensitivity; however, the insufficient stability of existing fluorescence sensing materials in aqueous phases limits their application in practical water sample testing. In contrast, colorimetric sensing offers ease of operation, low detection cost, and direct signal changes. Combined with portable devices such as mobile phones, it is suitable for rapid on-site screening and real-time visual detection. It demonstrates outstanding practicality in rapid qualitative, semi-quantitative analysis, and portable detection applications.
[0006] Therefore, how to develop a CsPbX3 quantum dot material that can maintain stable luminescence performance in polar environments and enable rapid and sensitive detection of analytes in water, while also taking into account the simplicity of the preparation process and its scalability, is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0007] In view of this, the purpose of this invention is to propose a lead halide perovskite quantum dot material, its preparation method and application, so as to solve the problem that existing lead halide perovskite quantum dots have poor structural stability in polar environments and cannot achieve rapid and sensitive detection of analytes in water.
[0008] To achieve the above objectives, the present invention provides a method for preparing lead halide perovskite quantum dot materials, comprising the following steps: S1: Mix lead source, 1-octadecene, oleylamine and oleic acid, add cesium source, and sonicate in an ultrasonic cleaner to obtain a mixture; S2: Place the mixture on a high-power ultrasonic instrument for low-power activation. After activation, increase the power to carry out ultrasonic synthesis reaction. After the reaction is completed, quickly cool to room temperature. S3: After centrifuging the solution, collect the solid, wash it with the first organic solvent, centrifuge again to collect the solid, repeat the washing process once or twice, and then disperse the solid in the second organic solvent; S4: Add a surfactant to the above solution, sonicate in an ultrasonic cleaner, and then activate it on a high-precision ultrasonic instrument to obtain lead halide perovskite quantum dot material.
[0009] Preferably, the lead source in step S1 is selected from at least one of PbCl2, PbBr2, PbI2, PbCO3, and (CH3COO)2Pb.
[0010] Preferably, the volume ratio of 1-octadecene to oleic acid in step S1 is 4:1 to 25:1.
[0011] Preferably, the volume ratio of 1-octadecene to oleylamine in step S1 is 4:1 to 25:1.
[0012] Preferably, the cesium source in step S1 is selected from at least one of CsCl, CsBr, CsI, and Cs2CO3.
[0013] Preferably, the molar ratio of cesium in the cesium source to lead in the lead source in step S1 is 0.3:1-2:1.
[0014] Preferably, the ultrasonic cleaner in step S1 has a power of 40-100W and a time of 10-30min.
[0015] Preferably, in step S2, the tip ultrasound working temperature is 20-60℃, the activation power is 50-100W, the activation time is 10-60min, the tip ultrasound reaction power is 150-600W, and the reaction time is 5-60min.
[0016] Preferably, the centrifugation speed in step S3 is 8000-12000 rpm and the centrifugation time is 5-10 min.
[0017] Preferably, in step S3, the first organic reagent is ethyl acetate, and the washing is performed 2-3 times.
[0018] Preferably, in step S3, the second organic reagent is selected from at least one of cyclohexane, n-hexane, isooctane, and n-heptane, and the volume is 300-1000 mL.
[0019] Preferably, the surfactant in step S4 is selected from one of AOT (sodium bis(2-ethylhexyl)sulfosuccinate), NaDEHP (sodium bis(2-ethylhexyl)phosphate), sodium lauryl phosphate, and sodium oleate.
[0020] Preferably, the molar concentration of the surfactant in the second organic reagent in step S4 is 0.03-0.5M.
[0021] Preferably, the ultrasonic cleaner in step S4 has a power of 40-100W, a time of 10-30min, a tip ultrasonic temperature of 20-60℃, an activation power of 50-120W, and an activation time of 10-60min.
[0022] Furthermore, the present invention also provides a lead halide perovskite quantum dot material, wherein the chemical formula of the lead halide perovskite quantum dot is CsPbX3; wherein the element at the X position is one or more of Cl, Br, and I.
[0023] Furthermore, the present invention also provides an application of lead halide perovskite quantum dot materials in the detection of analytes in water.
[0024] The steps for detecting the analyte in the water are as follows: A series of standard aqueous solutions of the analytes are prepared by mixing lead halide perovskite quantum dots with the standard solutions of the analytes to obtain a mixture. The mixture is then vortexed and ultrasonically cleaned to obtain a series of standard samples. Fluorescence spectra of the standard sample solutions are measured. A linear equation is obtained by analyzing the linear relationships between the peak height, peak area, and maximum emission wavelength of the characteristic peaks in the fluorescence spectra and the concentration of the analyte, or the linear relationship between the ratio of the peak areas of the characteristic peaks and the concentration of the analyte. Alternatively, colorimetry is performed on the standard sample solutions, and the colorimetric parameters (RGB values) are analyzed to determine the relationship between the RGB values and the concentration of the analyte. The linear relationship between the concentrations of the analytes and the concentrations of the analytes is established by obtaining a linear equation. Lead halide perovskite quantum dots are mixed with an aqueous solution of the actual sample of the analyte to obtain a mixture. This mixture is then vortexed and ultrasonically cleaned to obtain the actual sample. The fluorescence emission spectrum of the actual sample solution is measured to obtain the peak height, peak area, maximum emission wavelength, or peak area ratio of the characteristic peaks. These values are then substituted into the corresponding linear equations to calculate the concentration of the analyte. Alternatively, the RGB values of the colorimetric parameters of the actual sample solution are measured and substituted into the corresponding linear equations to calculate the concentration of the analyte. Preferably, the substance to be tested is one of chloride ions, bromide ions, iodide ions, copper ions, mercury ions, 3-chloro-1,2-propanediol, picric acid, and ciprofloxacin hydrochloride.
[0025] Preferably, the volume of the lead halide perovskite quantum dots is 5-20 mL.
[0026] Preferably, the volumes of the standard sample solution and the actual sample solution of the analyte are 0.018-1.0 mL.
[0027] Preferably, the vortex speed is 1500-2500 rpm and the vortex time is 3-20 min.
[0028] Preferably, the ultrasonic cleaner has a power of 40-100W and a time of 10-30 minutes.
[0029] The beneficial effects of this invention are: This application presents a simple processing method for preparing CsPbX3, a quantum dot material with excellent luminescence properties and high polar environment stability, providing an economical, simple, reliable and easy-to-operate method for the preparation of this type of material. The CsPbX3 quantum dots prepared in this application exhibit a continuous strong emission spectrum from blue to red light and high luminescence quantum efficiency. High-quality CsPbX3 quantum dots were obtained under advanced ultrasonic driving. Subsequent passivation and protection with surfactants significantly improved the stability of the CsPbX3 quantum dots in polar environments, demonstrating promising applications in optomagnetic fields such as sensing, fluorescent labeling, and detection. The method provided in this application overcomes the complex preparation process and harsh reaction conditions of the hot-injection method. The preparation method does not require an inert atmosphere and is simple and rapid, suitable for large-scale production. Furthermore, the method solves the problem of poor stability of CsPbX3 quantum dots in polar environments, further expanding the application areas of CsPbX3.
[0030] The application of CsPbX3-based detection of substances in water disclosed in this application is simple, convenient, accurate and efficient, and has good application prospects in the detection field. This application employs a simple, advanced ultrasonic method combined with the protective effect of surfactants to synthesize a CsPbX3 quantum dot solution exhibiting excellent luminescence properties and good stability in polar environments. In a reverse microemulsion system, the analyte in water is enriched and reacts with the CsPbX3 quantum dots at the microemulsion interface. The analyte is quantitatively analyzed by measuring changes in the luminescence properties of the reaction products or changes in the sample color. The CsPbX3 quantum dots synthesized in this application exhibit good and stable luminescence properties in polar environments, making them excellent fluorescent sensing materials. Detection applications developed based on this material are of great significance for expanding the application of perovskite materials and detecting substances in water. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Figure 1 The XRD pattern of CsPbBr3 prepared in Example 1 of this application; Figure 2 These are images of CsPbBr3 prepared in Example 1 of this application, with left: under sunlight and right: under 365nm ultraviolet light; Figure 3 Fluorescence spectra of the CsPbBr3 prepared in Example 1 of this application were obtained after reacting with standard chloride ion solutions of different concentrations in a reverse microemulsion system. Figure 4 This is a linear relationship graph between chloride ion concentration and the maximum emission wavelength of the characteristic peak of the reaction product in Example 1 of this application; Figure 5 This is a linear relationship graph between chloride ion concentration and the RGB color parameters of the reaction products in Example 1 of this application. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.
[0033] Example 1: A method for preparing lead halide perovskite quantum dot material (CsPbBr3 quantum dots), the specific steps of which are as follows: Weigh 0.2002 g PbBr2 into a 50 mL reaction flask. Then, sequentially add 12.0 mL of 1-octadecene, 0.5 mL of oleylamine, and 0.6 mL of oleic acid to the reaction flask. Next, weigh 0.0391 g Cs2CO3 into the reaction flask. Place the reaction flask in an ultrasonic cleaner and sonicate at 40 W for 10 min. Place the sonicated sample in a high-precision ultrasonic instrument and activate it at 20 °C under 50 W for 10 min. After activation, adjust the power to 150 W and sonicate for 10 min. After the reaction was completed, the reaction flask was rapidly cooled to room temperature. The sample after the reaction was centrifuged at 8000 rpm for 5 min. The obtained solid was washed twice with ethyl acetate. After washing, the obtained solid sample was dispersed in 600 mL of cyclohexane. 26.6735 g of AOT was added to the above solution, and the sample was placed in an ultrasonic cleaner and sonicated at 40 W for 10 min. Then, the sample was placed in a high-precision ultrasonic instrument and activated at 20 °C under 50 W for 10 min to obtain CsPbBr3 quantum dot material.
[0034] The specific steps for using the obtained CsPbBr3 quantum dot material to detect analytes in water are as follows: (1) Preparation of chloride ion standard solution: Prepare a series of standard aqueous solutions with a concentration of 10-500 µg / mL using NaCl standard; (2) Preparation of standard samples: 5.00 mL of SPbBr3 quantum dots were transferred into a reaction flask, 90 µL of chloride ion standard solution of the above concentration was added, the mixture was vortexed at 2000 rpm for 10 min, and then placed in an ultrasonic cleaner and sonicated at 100 W for 15 min to obtain standard samples. (3) Establishment of chloride ion standard curve: The fluorescence spectrum of the above standard sample was measured at the excitation wavelength of 365 nm. The linear equation was obtained based on the linear relationship between the emission wavelength of the characteristic peak and the chloride ion concentration; or the above standard sample was placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. The linear equation was obtained based on the linear relationship between B / (R+G) and chloride ion concentration. (4) Preparation of test sample containing chloride ions: Transfer 5.00 mL of SPbBr3 quantum dots into a reaction flask, add 90 µL of test sample solution, vortex at 2000 rpm for 10 min, and place in an ultrasonic cleaner and sonicate at 100 W for 15 min to obtain the test sample; (5) Determination of chloride ions in the sample to be tested: The fluorescence spectrum of the sample to be tested is measured at an excitation wavelength of 365 nm to obtain the characteristic peak emission wavelength of the sample to be tested. Based on the linear relationship established in step (3), the characteristic peak emission wavelength is substituted into the corresponding linear equation to calculate the concentration of chloride ions in the sample; or the sample to be tested is placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. B / (R+G) is substituted into the corresponding linear equation to calculate the concentration of chloride ions in the sample.
[0035] Example 2: A method for preparing lead halide perovskite quantum dot material (CsPbCl3 quantum dots), the specific steps of which are as follows: Weigh 0.1334 g PbCl2 into a 50 mL reaction flask. Then, sequentially add 13.0 mL of 1-octadecene, 0.6 mL of oleylamine, and 0.6 mL of oleic acid to the reaction flask. Next, weigh 0.1548 g CsCl and add it to the reaction flask. Place the reaction flask in an ultrasonic cleaner and sonicate at 90 W for 20 min. Place the sonicated sample in a high-precision ultrasonic instrument and activate it at 55 °C under 60 W for 30 min. After activation, adjust the power to 350 W and sonicate for 15 min. After the reaction is complete, quickly... The sample was rapidly cooled to room temperature and centrifuged at 9200 rpm for 8 min. The resulting solid was washed three times with ethyl acetate. After washing, the solid sample was dispersed in 500 mL of cyclohexane:n-heptane (v:v=1:1). 17.2635 g of sodium bis(2-ethylhexyl)phosphate was added to the above solution. The sample was then ultrasonicated at 90 W for 15 min in an ultrasonic cleaner. After that, the sample was activated at 110 W for 22 min at 50 °C in a high-precision ultrasonic instrument to obtain CsPbCl3 quantum dots. The specific steps for using the obtained CsPbCl3 quantum dot material to detect analytes in water are as follows: (1) Preparation of bromide ion standard solution: Prepare a series of standard aqueous solutions of 10-500µg / mL using NaBr standard; (2) Preparation of standard samples: 10.00 mL of SPbCl3 quantum dots were transferred into a reaction flask, 175 µL of bromide ion standard solution of the above concentration was added, the mixture was vortexed at 2200 rpm for 8 min, and then placed in an ultrasonic cleaner and sonicated at 90 W for 20 min to obtain standard samples. (3) Establishment of bromide ion standard curve: The fluorescence spectrum of the above standard sample was measured at an excitation wavelength of 365 nm. The linear equation was obtained based on the linear relationship between the characteristic peak emission wavelength and the bromide ion concentration; or the above standard sample was placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. The linear equation was obtained based on the linear relationship between B / (R+G) and the bromide ion concentration. (4) Preparation of test samples containing bromide ions: Transfer 10.00 mL of SPbCl3 quantum dots into a reaction flask, add 175 µL of the test sample solution, vortex at 2200 rpm for 8 min, and place in an ultrasonic cleaner and sonicate at 90 W for 20 min to obtain the test sample. (5) Determination of bromide ions in the sample to be tested: The fluorescence spectrum of the sample to be tested is measured at an excitation wavelength of 365 nm to obtain the characteristic peak emission wavelength of the sample to be tested. Based on the linear relationship established in (3), the characteristic peak emission wavelength is substituted into the corresponding linear equation to calculate the concentration of bromide ions in the sample; or the sample to be tested is placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. B / (R+G) is substituted into the corresponding linear equation to calculate the concentration of bromide ions in the sample.
[0036] Example 3: A method for preparing lead halide perovskite quantum dot material (CsPbI3 quantum dots), the specific steps of which are as follows: Weigh 0.1993 g PbI₂ into a 50 mL reaction flask. Then, sequentially add 10.0 mL of 1-octadecene, 1.0 mL of oleylamine, and 1.0 mL of oleic acid to the reaction flask. Next, weigh 0.0559 g CsI and add it to the reaction flask. Place the reaction flask in an ultrasonic cleaner and sonicate at 100 W for 30 min. Place the sonicated sample in a high-precision ultrasonic instrument and activate it at 100 W for 60 min at 60 °C. After activation, increase the power to 600 W and sonicate for another 60 min. After the reaction is complete, remove the reaction flask from the ultrasonic cleaner. The sample was rapidly cooled to room temperature and centrifuged at 12000 rpm for 5 min. The resulting solid was washed twice with ethyl acetate. After washing, the solid sample was dispersed in 450 mL of cyclohexane:n-heptane (v:v=7:3). 15.3459 g of sodium lauryl phosphate was added to the above solution. The sample was then ultrasonicated at 100 W for 30 min in an ultrasonic cleaner. After that, the sample was activated at 120 W for 60 min at 60 °C in a high-precision ultrasonic instrument to obtain CsPbI3 quantum dots. The specific steps for using the obtained CsPbI3 quantum dot material to detect analytes in water are as follows: (1) Preparation of bromide ion standard solution: Prepare a series of standard aqueous solutions of 10-500µg / mL using NaBr standard; (2) Preparation of standard samples: 10.00 mL of SPbI3 quantum dots were transferred into a reaction flask, 200 µL of bromide ion standard solution of the above concentration was added, the mixture was vortexed at 2500 rpm for 10 min, and then placed in an ultrasonic cleaner and sonicated at 80 W for 20 min to obtain standard samples. (3) Establishment of bromide ion standard curve: The fluorescence spectrum of the above standard sample was measured at an excitation wavelength of 365 nm. The linear equation was obtained based on the linear relationship between the characteristic peak emission wavelength and the bromide ion concentration; or the above standard sample was placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. The linear equation was obtained based on the linear relationship between B / (R+G) and the bromide ion concentration. (4) Preparation of test samples containing bromide ions: Transfer 10.00 mL of SPbI3 quantum dots into a reaction flask, add 200 µL of test sample solution, vortex at 2500 rpm for 10 min, and place in an ultrasonic cleaner and sonicate at 80 W for 20 min to obtain the test sample. (5) Determination of bromide ions in the sample to be tested: The fluorescence spectrum of the sample to be tested is measured at an excitation wavelength of 365 nm to obtain the characteristic peak emission wavelength of the sample to be tested. Based on the linear relationship established in (3), the characteristic peak emission wavelength is substituted into the corresponding linear equation to calculate the concentration of bromide ions in the sample; or the sample to be tested is placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. B / (R+G) is substituted into the corresponding linear equation to calculate the concentration of bromide ions in the sample.
[0037] Example 4: A method for preparing lead halide perovskite quantum dot material (CsPb(Br / I)3 quantum dots), the specific steps of which are as follows: Weigh 0.1102 g PbBr2 and 0.1052 g PbI2 into a 50 mL reaction flask. Then, sequentially add 15.0 mL of 1-octadecene, 1.2 mL of oleylamine, and 1.2 mL of oleic acid to the reaction flask. Next, weigh 0.0419 g Cs2CO3 into the reaction flask. Place the reaction flask in an ultrasonic cleaner and sonicate at 100 W for 18 min. Place the sonicated sample in a high-precision ultrasonic instrument and activate it at 50 °C under 60 W for 20 min. After activation, adjust the power to 350 W and sonicate for 15 min. After the reaction was completed, the reaction flask was rapidly cooled to room temperature. The sample after the reaction was centrifuged at 9300 rpm for 10 min. The obtained solid was washed three times with ethyl acetate. After washing, the obtained solid sample was dispersed in 500 mL of cyclohexane:n-heptane (v:v=1:1). 17.5950 g of sodium oleate was added to the above solution. The mixture was placed in an ultrasonic cleaner and sonicated at 100 W for 20 min. Then, it was placed in a high-precision ultrasonic instrument and activated at 120 W for 20 min at 50 °C to obtain CsPb(Br / I)3 quantum dots.
[0038] The specific steps for using the obtained CsPb(Br / I)3 quantum dot material to detect analytes in water are as follows: (1) Preparation of 3-chloro-1,2-propanediol standard solution: Prepare a series of standard aqueous solutions of 0.2-200 µg / mL using 3-chloro-1,2-propanediol standard; (2) Preparation of standard samples: 10.00 mL of SPb(Br / I)3 quantum dots were transferred into a reaction flask, and 162 µL of 3-chloro-1,2-propanediol standard solution of the above concentration was added. The mixture was vortexed at 2300 rpm for 15 min and then placed in an ultrasonic cleaner and sonicated at 100 W for 10 min to obtain the standard sample. (3) Establishment of the standard curve of 3-chloro-1,2-propanediol: The fluorescence spectrum of the above standard samples was measured at an excitation wavelength of 365 nm. The linear equation was obtained according to the linear relationship between the emission wavelength of the characteristic peak or the fluorescence intensity and the concentration of 3-chloro-1,2-propanediol. Alternatively, the above standard samples were placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. The linear equation was obtained according to the linear relationship between B / (R+G) and the concentration of 3-chloro-1,2-propanediol. (4) Preparation of test sample containing 3-chloro-1,2-propanediol: Transfer 10.00 mL of SPb(Br / I)3 quantum dots into a reaction flask, add 162 µL of test sample solution, vortex at 2300 rpm for 15 min, and place in an ultrasonic cleaner and sonicate at 100 W for 10 min to obtain the test sample; (5) Determination of 3-chloro-1,2-propanediol in the sample to be tested: The fluorescence spectrum of the sample to be tested is measured at an excitation wavelength of 365 nm to obtain the characteristic peak emission wavelength or fluorescence intensity of the sample to be tested. Based on the linear relationship established in step 4, the characteristic peak emission wavelength or fluorescence intensity is substituted into the corresponding linear equation to calculate the concentration of 3-chloro-1,2-propanediol in the sample; or the sample to be tested is placed in a colorimeter (or mobile phone colorimeter software) for colorimetric testing to obtain RGB values. B / (R+G) is substituted into the corresponding linear equation to calculate the concentration of 3-chloro-1,2-propanediol in the sample.
[0039] Data Analysis Depend on Figure 1 It is known that the diffraction peaks of the CsPbBr3 sample prepared in Example 1 of this application match the diffraction peaks in standard PDF card #97-009-7851, therefore the prepared sample is orthorhombic CsPbBr3.
[0040] Depend on Figure 2 It is known that the CsPbBr3 quantum dots prepared in Example 1 of this application are well dispersed in cyclohexane and emit a bright green color under a 365nm ultraviolet lamp.
[0041] Depend on Figure 3It can be seen that when chloride ions of different concentrations are reacted with CsPbBr3 in a reverse microemulsion system, and the fluorescence spectrum of the reaction product is tested, the maximum emission wavelength of the fluorescence characteristic peak at 521 nm changes with the increase of chloride ion concentration. Based on the above changes, a quantitative relationship between chloride ion concentration and the maximum emission wavelength of the characteristic peak can be established.
[0042] Depend on Figure 4 It can be seen that there is a good linear relationship between chloride ion concentration and the maximum emission wavelength of the characteristic peak of the reaction product, with a linear correlation coefficient R. 2 It is 0.9901.
[0043] Depend on Figure 5 It can be seen that there is a good linear relationship between chloride ion concentration and the color parameter B / (R+G) of the reaction product, with a linear correlation coefficient R. 2 It is 0.9920.
[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.
Claims
1. A method for preparing lead halide perovskite quantum dot materials, characterized in that, Includes the following steps: S1: Mix lead source, 1-octadecene, oleylamine and oleic acid, add cesium source, and sonicate in an ultrasonic cleaner to obtain a mixture; S2: Place the mixture on a high-power ultrasonic instrument for low-power activation. After activation, increase the power to carry out ultrasonic synthesis reaction. After the reaction is completed, quickly cool to room temperature. S3: After centrifuging the solution, collect the solid, wash it with the first organic solvent, centrifuge again to collect the solid, repeat the washing process once or twice, and then disperse the solid in the second organic solvent; S4: Add a surfactant to the above solution, sonicate in an ultrasonic cleaner, and then activate it on a high-precision ultrasonic instrument to obtain lead halide perovskite quantum dot material.
2. The preparation method according to claim 1, characterized in that, The lead source in step S1 is selected from at least one of PbCl2, PbBr2, PbI2, PbCO3, and (CH3COO)2Pb; the cesium source is selected from at least one of CsCl, CsBr, CsI, and Cs2CO3.
3. The preparation method according to claim 1, characterized in that, In step S1, the volume ratio of 1-octadecene to oleic acid is 4:1-25:1; the volume ratio of 1-octadecene to oleylamine is 4:1-25:
1.
4. The preparation method according to claim 1, characterized in that, The molar ratio of cesium in the cesium source to lead in the lead source in step S1 is 0.3:1-2:
1.
5. The preparation method according to claim 1, characterized in that, In step S2, the working temperature of the tip ultrasound is 20-60℃, the activation power is 50-100W, the activation time is 10-60min, the tip ultrasound reaction power is 150-600W, and the reaction time is 5-60min.
6. The preparation method according to claim 1, characterized in that, In step S3, the first organic reagent is ethyl acetate; the second organic reagent is selected from at least one of cyclohexane, n-hexane, isooctane, and n-heptane.
7. The preparation method according to claim 1, characterized in that, The surfactant mentioned in step S4 is selected from one of AOT (sodium bis(2-ethylhexyl)sulfosuccinate), NaDEHP (sodium bis(2-ethylhexyl)phosphate), sodium lauryl phosphate, and sodium oleate.
8. The preparation method according to claim 1, characterized in that, The ultrasonic cleaner described in step S4 has a power of 40-100W, a time of 10-30min, a tip ultrasonic temperature of 20-60℃, an activation power of 50-120W, and an activation time of 10-60min.
9. A lead halide perovskite quantum dot material, characterized in that, It is prepared according to any one of claims 1-8.
10. An application of the lead halide perovskite quantum dot material according to claim 9, characterized in that, Applications in detecting substances in water.