CN111518559A

CN111518559A - Preparation method and application of high-stability perovskite quantum dot fluorescence sensor

Info

Publication number: CN111518559A
Application number: CN202010357522.2A
Authority: CN
Inventors: 卫潇; 王通; 陈贝; 秦昉; 张珅
Original assignee: Changan University
Current assignee: Changan University
Priority date: 2020-04-29
Filing date: 2020-04-29
Publication date: 2020-08-11
Anticipated expiration: 2040-04-29
Also published as: CN111518559B

Abstract

The invention discloses a preparation method of a high-stability perovskite quantum dot, which is characterized in that under the condition of room temperature, lead bromide and cesium bromide are used as precursors, and 3-aminopropyl triethoxysilane and oleic acid are used as ligands to prepare a perovskite quantum dot fluorescence sensor; the invention also discloses application of the perovskite quantum dot fluorescence sensor in alcohol phase tetracycline detection. According to the invention, a supersaturated recrystallization method at room temperature is adopted, and the perovskite quantum dot surface is coated with a silicon layer by 3-aminopropyltriethoxysilane for modification, so that the perovskite quantum dot fluorescent sensor is obtained, the oxidation inactivation of the perovskite quantum dot is avoided, and the stability of the perovskite quantum dot is improved, so that the perovskite quantum dot fluorescent sensor is stably dispersed in a high-polarity solvent; the amino group on the surface of the perovskite quantum dot fluorescence sensor has specific recognition and combination effects with tetracycline molecules, so that the fluorescence detection of tetracycline in an alcohol phase is realized, and the perovskite quantum dot fluorescence sensor has the advantages of high selectivity and high sensitivity.

Description

Preparation method and application of high-stability perovskite quantum dot fluorescence sensor

Technical Field

The invention belongs to the technical field of preparation of environment functional materials, and particularly relates to a preparation method and application of a high-stability perovskite quantum dot fluorescence sensor.

Background

Tetracyclines antibiotics are broad-spectrum antibiotics with a phenanthrene mother nucleus discovered in 40 th of the 20 th century, and are widely applied to infections caused by gram-positive and gram-negative bacteria, intracellular mycoplasma, chlamydia and rickettsia. Due to the characteristics of high quality, low price, good stability, promotion of crop growth under low concentration, rapid sterilization under high concentration and the like, the fertilizer is more and more frequently used in the agriculture and livestock husbandry. After the tetracycline antibiotics enter soil or water environment, bacteria and microorganisms in the soil or water body may be killed or resistance genes are generated, so that the ecological environment is damaged; meanwhile, after entering a human body in a biological enrichment mode, the biological enrichment can cause serious harm to the human body, including tooth yellowing, anaphylactic reaction, liver injury and even gastrointestinal tract disorder. Therefore, the detection of tetracycline in the environment is not very slow. The traditional detection method has the defects of complex operation, long detection time, higher cost and poor selectivity, and the defects limit the application of tetracycline antibiotics in the detection environment

The fluorescence analysis method is an analysis method which is established based on the special property of fluorescence, can convert the fluorescence phenomenon into fluorescence spectrum through a fluorescence spectrophotometer, and can realize qualitative and quantitative analysis of substances according to the fluorescence spectrum. The fluorescence analysis method is a novel detection method and has the characteristics of simple operation, rapid reaction, low detection limit, high sensitivity and the like. When the fluorescent probe reacts with the analyzed substrate, the fluorescence spectrum changes in intensity, wavelength and the like, and the existence of the substrate can be analyzed by detecting the change of the fluorescence spectrum, and the substrate can be quantitatively analyzed.

Quantum Dots (QDs) are zero-dimensional semiconductor nanocrystals, typically 1.0nm to 10nm in size, which are aggregates of nanoscale molecules and atoms. Compared with the traditional organic dye and rare earth luminescent material, the quantum dot has more excellent properties, such as adjustable physicochemical properties, easy modification, high quantum dot yield, high sensitivity and good optical stability, and is an ideal fluorescent probe. However, the quantum yield of the traditional quantum dot is low, and the sensitivity of the fluorescence sensor prepared by surface modification is low. Therefore, it is necessary to develop a novel semiconductor quantum dot having excellent photoluminescence properties and high fluorescence quantum yield.

Recently, CsPbX₃Perovskite Quantum Dots (IPQDs) attract attention of researchers due to excellent fluorescence properties of the perovskite quantum dots, the novel perovskite quantum dots have the advantages of halide perovskites and quantum dots, show 90% of luminous efficiency, narrow fluorescence half-peak width and adjustable fluorescence emission, are superior to most of traditional quantum dots even after surface modification, and have great prospects when being applied to the field of fluorescence detection.

At present, the research reports on perovskite quantum dots are increasing. "Visual and sensory fluorine sensing for ultra genetic entities by Perovkite quality dots", Lu et al 2017, Analytica Chimica Acta; "All-inorganic peroxide quats CsPbX3(Br/I) for high purity sensitive and selective detection of additive polymeric acid", Chen et al published in chemical engineering Journal by 2015; huang et al 2018, "Novel fluorine Based Sensor Based on one all-Inorganic Perovskite Quantum Dots Coated with molecular imprinting polymers for high choice and Sensitive Detection of Omethoate". In all three documents, a fluorescent sensor system is constructed in an oil phase through novel perovskite quantum dots, and the construction of a fluorescent tetracycline sensor system in an alcohol phase is not reported.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of a high-stability perovskite quantum dot fluorescence sensor aiming at the defects of the prior art. According to the method, a supersaturated recrystallization method at room temperature is adopted, and 3-Aminopropyltriethoxysilane (APTES) is used for coating a silicon layer on the surface of perovskite quantum dots (IPQDs) for modification, so that the perovskite quantum dot fluorescence sensor (APTES @ IPQDs) is obtained, the oxidation inactivation of the perovskite quantum dots is avoided, the stability of the perovskite quantum dots is improved, and the perovskite quantum dot fluorescence sensor is stably dispersed in a high-polarity solvent.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: the preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized in that lead bromide and cesium bromide are used as precursors, and 3-aminopropyl triethoxysilane and oleic acid are used as ligands to prepare the perovskite quantum dot fluorescence sensor at room temperature.

The preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized by comprising the following steps of:

adding lead bromide and cesium bromide into a benign solvent, and stirring until the lead bromide and the cesium bromide are completely dissolved to obtain a precursor solution;

step two, adding oleic acid and 3-aminopropyl triethoxysilane ligand into the precursor solution obtained in the step one, and stirring and mixing uniformly to obtain a mixed solution;

step three, injecting the mixed solution obtained in the step two into dichloromethane which is being stirred, and continuously stirring uniformly to obtain a mixed product;

and step four, washing and centrifuging the mixed product obtained in the step three by adopting n-hexane and dichloromethane in turn, and obtaining the precipitate as the perovskite quantum dot fluorescence sensor.

The preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized in that in the step one, the mass ratio of the lead bromide to the cesium bromide is 1:1, and the benign solvent is N, N-dimethylformamide or dimethyl sulfoxide.

The preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized in that the volume ratio of oleic acid to 3-aminopropyltriethoxysilane in the step two is 1: (0.1-0.2).

The preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized in that the volume ratio of the mixed solution to the dichloromethane in the third step is 1: (5-10), and the time for uniformly stirring is 20-30 min.

The preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized in that the centrifugation speed in the fourth step is 8000-12000 rpm.

In addition, the invention also provides application of the high-stability perovskite quantum dot fluorescence sensor in alcohol phase tetracycline detection.

The structural schematic diagram of the combination of APTES @ IPQDs prepared by the invention and tetracycline is shown in figure 1: 3-Aminopropyltriethoxysilane (APTES) is used as a raw material to coat a silicon layer on the surface of IPQDs for modification, so that the perovskite quantum dot fluorescence sensor is stably dispersed in a high-polarity solvent, and meanwhile, the amino on the surface of the perovskite quantum dot and tetracycline molecules have specific recognition and combination effects, and the fluorescence detection of tetracycline in an alcohol phase is realized.

Compared with the prior art, the invention has the following advantages:

1. according to the invention, a supersaturated recrystallization method at room temperature is adopted, 3-aminopropyl triethoxysilane (APTES) is used as a raw material, and the characteristic that APTES absorbs water in air to decompose is utilized to enable the APTES to coat a silicon layer on the surface of a perovskite quantum dot to be modified, so that the perovskite quantum dot fluorescence sensor (APTES @ IPQDs) with uniform particle size and good dispersibility is obtained, and the problems that the perovskite quantum dot is poor in stability, is easy to oxidize when exposed in air and is easy to lose activity when exposed in water are solved, so that the perovskite quantum dot fluorescence sensor is stably dispersed in a high-polarity solvent, and the stability of the perovskite quantum dot fluorescence sensor is improved.

2. The preparation method of the perovskite quantum dot fluorescence sensor is simple and convenient, low in equipment requirement, high in yield and easy to realize.

3. The perovskite quantum dot fluorescence sensor prepared by the invention has stable fluorescence property dispersed in a high-polarity solvent, has higher fluorescence quantum yield, and realizes the fluorescence detection of tetracycline in an alcohol phase by the specific recognition and combination action of amino on the surface of the perovskite quantum dot fluorescence sensor and tetracycline molecules.

4. The perovskite quantum dot fluorescence sensor has high selectivity and high sensitivity to tetracycline in an alcohol phase, and is favorable for rapidly identifying and detecting tetracycline antibiotics on site.

The technical solution of the present invention is further described in detail by the accompanying drawings and examples.

Drawings

FIG. 1 is a schematic diagram of the structure of the combination of APTES @ IPQDs prepared in the present invention and tetracycline.

FIG. 2 is a fluorescence spectrum of APTES @ IPQDs prepared in example 1 of the present invention.

FIG. 3 is a FT-IR spectrum of APTES @ IPQDs prepared in example 1 of the present invention.

FIG. 4 is a graph of the stability of APTES @ IPQDs prepared in example 1 of the present invention in ethanol.

FIG. 5 is a graph showing the effect of tetracycline action time of the present invention on the fluorescence intensity of APTES @ IPQDs.

FIG. 6 is a graph showing the effect of tetracycline concentration of the present invention on the fluorescence intensity of APTES @ IPQDs.

FIG. 7 is a line fit plot of the effect of tetracycline concentration of the present invention on APTES @ IPQDs fluorescence intensity.

FIG. 8 is a graph showing the selectivity of APTES @ IPQDs prepared in example 1 of the present invention versus different antibiotics.

Detailed Description

The preparation method of the high-stability perovskite quantum dot fluorescence sensor of the invention is described in detail through examples 1 to 5.

The application of the high stability perovskite quantum dot fluorescence sensor of the present invention is described in detail by example 6.

Example 1

The embodiment comprises the following steps:

step one, adding 0.4mmol of lead bromide and 0.4mmol of cesium bromide into 10mL of N, N-Dimethylformamide (DMF), and stirring until the lead bromide and the cesium bromide are completely dissolved to obtain a precursor solution;

step two, adding 1.0mL of oleic acid and 0.15mL of APTES ligand into the precursor solution obtained in the step one, and stirring and mixing uniformly to obtain a mixed solution;

step three, injecting 1.0mL of the mixed solution obtained in the step two into 10mL of dichloromethane which is being stirred, and continuously stirring uniformly for 30min to obtain a mixed product;

and step four, washing and centrifuging the mixed product obtained in the step three by adopting n-hexane and dichloromethane in turn and alternately, wherein the centrifuging speed is 10000rpm, and the obtained precipitate is the perovskite quantum dot fluorescence sensor.

FIG. 2 is a fluorescence spectrum of APTES @ IPQDs prepared in this example, and it can be seen from FIG. 2 that APTES @ IPQDs prepared in this example have a distinct characteristic peak at 512nm and a narrow half-peak width (about 28nm), indicating that the APTES @ IPQDs have strong emission fluorescence properties. In addition, the APTES @ IPQDs prepared in this example have a distinct characteristic peak at 512nm as detected by UV and visible light.

FIG. 3 is the FT-IR spectrum of APTES @ IPQDs prepared in this example, which can be seen from FIG. 3, 946cm^-1The weak absorption band was due to Si-OH stretching, indicating that APTES was hydrolytically condensed, 1045cm^-1The peak at (A) was derived from the vibration of Si-O-C at 1125cm^-1The absorption peak at (a) was attributed to the vibration of Si-O-Si, which indicates that a silicon dioxide layer was formed; at 1538cm^-1And 3438cm^-1The absorption peaks at (A) correspond to the bending vibration and the stretching vibration of N-H, 2855cm^-1And 2928cm^-1The absorption peak at (A) is due to C-H tensile vibration, indicating that the surface of APTES @ IPQDs prepared in this example have amino groups.

FIG. 4 is a graph showing the stability of APTES @ IPQDs prepared in this example in ethanol, and it can be seen from FIG. 4 that the fluorescence intensity of APTES @ IPQDs prepared in this example is almost unchanged within 60min, which shows that the APTES @ IPQDs can be stably dispersed in ethanol.

Example 2

The embodiment comprises the following steps:

step one, adding 0.4mmol of lead bromide and 0.4mmol of cesium bromide into 10mL of dimethyl sulfoxide (DMSO), and stirring until the lead bromide and the cesium bromide are completely dissolved to obtain a precursor solution;

step two, adding 1.0mL of oleic acid and 0.10mL of APTES ligand into the precursor solution obtained in the step one, and stirring and mixing uniformly to obtain a mixed solution;

and step four, washing and centrifuging the mixed product obtained in the step three by adopting n-hexane and dichloromethane in turn, wherein the centrifuging speed is 12000rpm, and the obtained precipitate is the perovskite quantum dot fluorescence sensor.

Example 3

The embodiment comprises the following steps:

step two, adding 1.0mL of oleic acid and 0.20mL of APTES ligand into the precursor solution obtained in the step one, and stirring and mixing uniformly to obtain a mixed solution;

and step four, washing and centrifuging the mixed product obtained in the step three by adopting n-hexane and dichloromethane in turn, wherein the centrifuging speed is 8000rpm, and the obtained precipitate is the perovskite quantum dot fluorescence sensor.

Example 4

The embodiment comprises the following steps:

step three, injecting 2.0mL of the mixed solution obtained in the step two into 10mL of dichloromethane which is being stirred, and continuously stirring uniformly for 20min to obtain a mixed product;

Example 5

The embodiment comprises the following steps:

step three, injecting 1.5mL of the mixed solution obtained in the step two into 10mL of dichloromethane which is being stirred, and continuously stirring uniformly for 25min to obtain a mixed product;

Example 6

The application process of this embodiment is: APTES @ IPQDs prepared in example 1 is prepared into 50mg/L APTES @ IPQDs solution, tetracycline is dissolved in ethanol to prepare 1mmol/L tetracycline ethanol solution, and then 3mL of 50mg/LAPTES @ IPQDs solution and 0.1mL of 1mmol/L tetracycline ethanol solution are mixed uniformly to form mixed solution and are kept stand.

The APTES @ IPQDs of this example can also be the APTES @ IPQDs prepared in example 2 or example 3.

The application performance of the APTES @ IPQDs in the alcohol phase tetracycline detection is evaluated.

Preparing a solvent: adding the APTES @ IPQDs prepared in the example 1 into deionized water to prepare 50g/L solution of the APTES @ IPQDs; dissolving tetracycline in ethanol to prepare a 1mmol/L tetracycline ethanol solution.

(1) Effect of Tetracycline Effect time on APTES @ IPQDs fluorescence intensity

Adding 3mL of 50mg/L APTES @ IPQDs solution and 0.1mL of 1mmol/L tetracycline ethanol solution into a test tube, metering the volume to 10mL by using absolute ethanol, uniformly mixing, and standing to prepare a sample solution; adding 3mL of 50mg/L APTES @ IPQDs solution into a test tube, metering the volume to 10mL by using absolute ethyl alcohol, uniformly mixing, and standing to prepare a blank solution; respectively measuring the fluorescence intensity F of the sample solution and the fluorescence intensity F of the blank solution by using a fluorescence photometer at 3min, 5min, 7min, 10min, 13min, 15min, 17min, 20min, 25min and 30min after standing₀. The standing time is taken as the abscissa, F/F₀The results are shown in FIG. 5, plotted for the ordinate.

FIG. 5 is a graph showing the effect of the tetracycline action time on the fluorescence intensity of APTES @ IPQDs, and it can be seen from FIG. 5 that the fluorescence intensity rapidly decreases and the fluorescence quenching phenomenon is strong when APTES @ IPQDs are mixed with tetracycline ethanol solution and then kept still for 1min to 7 min; and (3) the fluorescence intensity is reduced more slowly and gradually tends to be stable in the 7 th to 15 th min after standing, and the fluorescence intensity is kept stable after the 15 th min, so that the adsorption structures of the APTES @ IPQDs and tetracycline molecules reach an equilibrium state.

(2) Effect of Tetracycline Effect time on APTES @ IPQDs fluorescence intensity

Adding 3mL of 50mg/L APTES @ IPQDs solution into 0mL, 0.005mL, 0.008mL, 0.010mL, 0.015mL, 0.02mL, 0.03mL, 0.04mL, 0.05mL, 0.06mL, 0.07mL, 0.08mL, 0.10mL, 0.12mL, 0.15mL of 1mmol/L tetracycline ethanol solution, adding anhydrous ethanol to a test tube, diluting to 10mL, mixing well, and standing to obtain 15 groups of sample solutions, wherein the concentration of tetracycline in each group of test tube is 0 μmol/L, 0.5 μmol/L, 0.8 μmol/L, 1 μmol/L, 1.5 μmol/L, 2 μmol/L, 3 μmol/L, 4 μmol/L, 5 μmol/L, 6 μmol/L, 7 μmol/L, 8 μmol/L, 10 μmol/L, 12 μmol/L, or the likeL/L and 15 mu mol/L, and simultaneously adding 3mL of 50mg/L APTES @ IPQDs solution into a test tube, and metering the volume to 10mL by using absolute ethyl alcohol to obtain a blank solution; standing for 15min, and measuring the fluorescence intensity F and the blank solution F of each group of sample solution respectively by using a fluorescence photometer₀Drawing the fluorescence property change curve of each group of sample solution by taking the wavelength as an abscissa and the fluorescence intensity F of each group of sample solution as an ordinate, and according to the Stern-Volmer equation F_Q/F＝1+K_SYC Linear fitting and plotting, wherein F₀Fluorescence intensity of blank solution, F fluorescence intensity of each group of sample solutions, K_svC is the concentration of the sample solution, resulting in a linear fit equation Y of 1.0046+0.32695X, where Y represents F₀and/F, X represents the concentration of the tetracycline sample in the solution.

FIG. 6 is a graph showing the effect of tetracycline concentration on the fluorescence intensity of APTES @ IPQDs, and it can be seen from FIG. 6 that the fluorescence intensity of the fluorescence sensor gradually decreases with the increase of tetracycline concentration in the sample solution, i.e., a fluorescence quenching phenomenon occurs, which shows that the specific binding between APTES @ IPQDs and tetracycline occurs in the sample solution, and the higher the tetracycline concentration is, the higher the degree of interaction between APTES @ IPQDs and tetracycline is, the more obvious the fluorescence quenching phenomenon in the sample solution is.

FIG. 7 is a linear fitting graph of the influence of tetracycline concentration on APTES @ IPQDs fluorescence intensity, and the correlation coefficient of a linear fitting equation corresponding to the linear fitting graph is 0.99763, which shows that the perovskite quantum dot fluorescence sensor of the present invention has high detection accuracy, i.e., high sensitivity, when being used for detecting tetracycline in an alcohol phase, and can be used for detecting trace tetracycline in the alcohol phase.

(3) Selectivity of APTES @ IPQDs for tetracycline antibiotics

Respectively adding 3mL of 50mg/L APTES @ IPQDs solution and 0.10mL of 1mmol/L ethanol solution of different antibiotics into a test tube, metering the volume to 10mL by using absolute ethanol, and uniformly mixing to prepare a sample solution; adding 3mL of 50mg/L APTES @ IPQDs solution into a test tube, diluting to 10mL with ethanol, and mixing uniformly to obtain a blank solution; standing for 15min, and measuring the fluorescence intensity F of each sample solution and the fluorescence intensity of the blank solution respectively by using a fluorescence photometerDegree F₀. Taking the serial number of substrate antibiotics (sequentially numbering tetracycline, sulfadiazine, doxycycline and azithromycin as 1, 2, 3 and 4) as the abscissa, and taking the fluorescence quenching rate (F) of the action of APTES @ IPQDs and the substrate₀/F-1) is plotted as a bar graph on the ordinate, and the results are shown in FIG. 8.

FIG. 8 is a graph comparing the selectivity of APTES @ IPQDs prepared in example 1 of the present invention to different antibiotics, and it can be seen from FIG. 8 that only tetracycline causes a significant change in the fluorescence quenching rate of APTES @ IPQDs, resulting in fluorescence quenching, while other antibiotics have little effect on the fluorescence intensity of APTES @ IPQDs, indicating that the APTES @ IPQDs of the present invention have excellent selectivity to tetracycline.

The above description is only an embodiment of the preferred ingredient range of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. The preparation method of the high-stability perovskite quantum dot fluorescence sensor is characterized in that lead bromide and cesium bromide are used as precursors, and 3-aminopropyl triethoxysilane and oleic acid are used as ligands to prepare the perovskite quantum dot fluorescence sensor at room temperature.

2. The preparation method of the high-stability perovskite quantum dot fluorescence sensor according to claim 1, characterized by comprising the following steps:

3. The method for preparing a high-stability perovskite quantum dot fluorescence sensor according to claim 2, wherein the mass ratio of the lead bromide to the cesium bromide in the first step is 1:1, and the benign solvent is N, N-dimethylformamide or dimethyl sulfoxide.

4. The method for preparing a high-stability perovskite quantum dot fluorescence sensor according to claim 2, wherein the volume ratio of the oleic acid to the 3-aminopropyltriethoxysilane in the second step is 1: (0.1-0.2).

5. The method for preparing a high-stability perovskite quantum dot fluorescence sensor according to claim 2, wherein the volume ratio of the mixed solution to dichloromethane in the step three is 1: (5-10), and the time for uniformly stirring is 20-30 min.

6. The method for preparing a high-stability perovskite quantum dot fluorescence sensor according to claim 2, wherein the centrifugation speed in the fourth step is 8000-12000 rpm.

7. The application of the perovskite quantum dot fluorescence sensor with high stability prepared by the method as claimed in any one of claims 1 to 6 in alcohol phase tetracycline detection.