Preparation method of lead ion fluorescence detection tool

Abstract

The present invention provides a method for preparing a lead ion fluorescence detection tool, which belongs to the technical field of luminescent materials. 2+ The CH 3 NH 3 Br or CsBr ligands, lead ion fluorescence detection tools are prepared on different substrates; wherein, a solution containing lead ions is titrated onto the prepared lead ion fluorescence detection tool to generate a sample, and the lead ion concentration is judged according to the change in the fluorescence intensity of the sample. The pretreatment of the substrate of the present invention can improve the film forming rate, and the prepared film and test paper are dense and uniform, without holes and cracks; according to the different properties of different perovskite materials and substrates, the preparation method can be flexibly selected to reduce the production cost of the product and improve the efficiency of the product; the prepared portable detection film and test paper are low-cost, non-toxic and harmless; the use of perovskite fluorescent materials is expanded, and other heavy metal fluorescence detection test papers can be prepared.

Description

Technical Field

[0001] The invention relates to the technical field of luminescent materials, and in particular to a method for preparing a lead ion fluorescence detection tool. Background Art

[0002] At present, the lead ion detection technology is mainly divided into: electrochemical analysis, liquid chromatography analysis, atomic absorption spectrometry, dithizone method, bioanalysis, etc. Among them, the dithizone method is widely used as the national standard method. The dithizone method can be divided into colorimetry and spectrophotometry. It is a method that uses the chemical properties of lead and dithizone to generate a red complex in a slightly alkaline solution, or directly visually compares the color after extraction, or combines a spectrophotometer to measure the absorbance to determine the lead ion content. Most of these methods are complicated to operate and have high costs. The Pb detection test paper currently on the market that uses the visual colorimetry method is a semi-quantitative test paper that needs to be compared with a colorimetric card and cannot directly detect colored liquids. The test paper generally needs to be stored in the dark within the range of 10-20°C, and the storage conditions are more restricted. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing a lead ion fluorescence detection tool to solve at least one technical problem existing in the above-mentioned background technology.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for preparing a lead ion fluorescence detection tool, comprising:

[0006] Will be able to and Pb 2+ A ligand containing CH3NH3Br or CsBr that reacts to form perovskite and exhibits photoluminescence properties is used to prepare a lead ion fluorescence detection tool on different substrates; wherein a solution containing lead ions is titrated onto the prepared lead ion fluorescence detection tool to generate a sample, and the lead ion concentration is determined based on changes in the fluorescence intensity of the sample.

[0007] Optionally, a lead ion fluorescence detection tool is prepared on a different substrate, and the lead ion fluorescence detection tool is a CH3NH3Br fluorescence detection film.

[0008] Furthermore, preparing a CH3NH3Br fluorescence detection film includes: selecting CH3NH3Br powder and mixing it with N,N-dimethylformamide to prepare a CH3NH3Br solution, and stirring to make the solutes mix evenly; spin coating the CH3NH3Br solution on a glass slide substrate to obtain a CH3NH3Br film.

[0009] Furthermore, the purity of the CH3NH3Br powder is above 99.9%; the concentration of the CH3NH3Br solution is 3M.

[0010] Furthermore, a desktop coating machine was used to spin coat the CH3NH3Br solution. The coating speed was controlled at 5000 rpm and the coating time was 30 s. The film was uniform and dense.

[0011] Optionally, a lead ion fluorescence detection tool is prepared on a different substrate, and the lead ion fluorescence detection tool is a CsBr fluorescence detection film and test paper.

[0012] Furthermore, the preparation of CsBr fluorescence detection film and test paper includes: evenly spreading CsBr powder on the bottom of the molybdenum boat, fixing a glass slide and wax paper on a substrate above the molybdenum boat in the evaporation chamber; lowering the bell jar, and evacuating the evaporation reaction chamber to a high vacuum state; setting the substrate rotation speed, selecting a suitable current for an evaporation experiment, and obtaining a CsBr film and test paper.

[0013] Furthermore, the purity of CsBr powder is above 99.9%; the wax paper is purged with a nitrogen gun; the vacuum degree of the evaporation reaction chamber is 2×10 -3 Pa or above.

[0014] Furthermore, the glass slide is treated as follows: the glass slide is first cleaned with water, ultrasonically cleaned in a pure solvent of ethanol, and then ultrasonically vibrated in deionized water, and the dried glass slide is placed in an ultraviolet cleaning machine for irradiation for standby use.

[0015] Furthermore, the substrate rotation speed is 5 r / min, the evaporation current is 90 A, the evaporation time is 5 min, and the film thickness reaches 400-500 nm.

[0016] The present invention has the following beneficial effects: the pretreatment of the substrate can improve the film forming rate, and the prepared film and test paper are dense and uniform without holes and cracks; the preparation method can be flexibly selected according to the different properties of different perovskite materials and substrates to reduce the production cost of the product and improve the efficiency of the product; the prepared portable detection film and test paper are low-cost, non-toxic and harmless; the use of perovskite fluorescent materials is expanded, and other heavy metal fluorescent detection test papers can be prepared.

[0017] Additional advantages of the present invention will be more clearly presented in the following description or learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0019] Figure 1 This is a photoluminescence spectrum of the CH3NH3Br film described in an embodiment of the present invention to different concentrations of lead ions.

[0020] Figure 2 The photoluminescence spectra of the CsBr film described in the embodiment of the present invention to different concentrations of lead ions are shown.

[0021] Figure 3 The photoluminescence spectra of the CsBr test paper described in the embodiment of the present invention for different concentrations of lead ions are shown in FIG. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below by the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0023] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0024] It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have a meaning consistent with that in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless as defined herein.

[0025] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0027] To facilitate understanding of the present invention, the present invention is further explained below with reference to specific embodiments in conjunction with the accompanying drawings, and the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0028] Those skilled in the art should understand that the drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily necessary for implementing the present invention.

[0029] Organic-inorganic hybrid perovskite materials have excellent optoelectronic properties and can be used in the fields of luminescent materials and devices, photovoltaic devices, etc. CH3NH3PbBr3 and CsPbBr3 perovskite materials emit strong green fluorescence under ultraviolet light and have high photoluminescence quantum yield, which is very suitable for use in LED device research. The photoluminescence properties of CH3NH3PbBr3 and CsPbBr3 films are very sensitive to lead ions. During the preparation of the materials, CH3NH3Br and CsBr ligands can react with Pb 2+ Rapid reaction forms perovskite, thus showing photoluminescence performance. Utilizing this feature, high-quality CH3NH3Br and CsBr films can be prepared on different substrates, and different concentrations of lead ion solutions can be titrated onto CH3NH3Br and CsBr films to quickly generate CH3NH3PbBr3 and CsPbBr3 samples, and the lead ion concentration can be determined based on the change in sample fluorescence intensity. It relies on photoluminescence intensity to determine the lead ion concentration, is not limited by the color of the sample being tested, and is easier to preserve. Therefore, in the embodiments of the present invention, the excellent fluorescence properties of the perovskite material are fully utilized to prepare an environmentally friendly, portable, and inexpensive lead ion fluorescence detection film and test paper.

[0030] Example 1

[0031] In this embodiment 1, a method for preparing a CH3NH3Br fluorescence detection film for lead ions is provided, which specifically includes:

[0032] (1) CH3NH3Br powder with a purity of 99.9% was selected and mixed with N,N-dimethylformamide (DMF) to prepare a CH3NH3Br solution with a concentration of 3.2 M;

[0033] (2) Magnetic stirring for 10-15 min to mix the solute evenly;

[0034] (3) The solution was spin-coated on a glass slide substrate in air to obtain a CH3NH3Br thin film.

[0035] In step (1), the purity of CH3NH3Br powder should be above 99.9%. In order to make the prepared film have high detection sensitivity, the concentration of CH3NH3Br solution should be close to the saturation concentration at room temperature, preferably 3M.

[0036] The stirring time in step (2) should be controlled according to the amount of solution. If the time is too long, the solvent will evaporate easily, and if the time is too short, the solute cannot be fully dissolved. Preferably, the stirring time for 2 ml of solution is controlled within 10 minutes.

[0037] In step (3), the spin coating speed of the desktop coating machine should be controlled at 5000 rpm, the spin coating time should be 30 seconds, and the film should be uniform and dense. In step (3), the glass slide is treated as follows: the glass slide is first cleaned with water, ultrasonically cleaned in pure ethanol solvent for 15 minutes, and then ultrasonically vibrated in deionized water for 15 minutes, and the dried glass slide is placed in a UV cleaning machine and irradiated for 30 minutes for use.

[0038] Different concentrations of Pb 2+ The PbBr2 solutions of different concentrations were titrated on the CH3NH3Br film, which emitted green light under ultraviolet light. The photoluminescence spectrum was further tested, such as Figure 1 As shown, the film has a 2+ The detection sensitivity of the concentration reaches 1×10 -4 M is a qualified sample.

[0039] Example 2

[0040] In this embodiment 2, a method for preparing a CsBr fluorescence detection film and a test paper for lead ions is provided, comprising:

[0041] (1) CsBr powder with a purity of 99.9% was evenly spread on the bottom of the molybdenum boat, and a glass slide and wax paper were fixed on the substrate above the molybdenum boat in the evaporation chamber.

[0042] (2) Lower the bell jar and evacuate the evaporation reaction chamber to a high vacuum state.

[0043] (3) Set the substrate rotation speed and select the appropriate current for evaporation experiment to obtain CsBr film and test paper.

[0044] In step (1), the purity of CsBr powder should be above 99.9%. The treatment of the glass slide is the same as that of the organic fluorescence detection film, and the wax paper is purged with a nitrogen gun.

[0045] In step (2), the vacuum degree of the evaporation reaction chamber should reach 2×10 -3 Pa or above.

[0046] In step (3), in order to ensure uniform film formation, the substrate rotation speed is preferably 5r / min. If the evaporation current is too large, the sample may easily splash out of the molybdenum boat. Preferably, the evaporation current should be 90A, and the evaporation time should be 5min. The film thickness should reach 400-500nm.

[0047] Different concentrations of Pb 2+The PbBr2 solution with different concentrations was titrated on the CsBr film and the test paper, respectively, and emitted green light under ultraviolet light, and further photoluminescence spectrum test was carried out, such as Figure 2 and Figure 3 As shown, the film's resistance to Pb 2+ The detection sensitivity of the concentration should reach 1.6×10 -5 M, test paper for Pb 2+ The detection sensitivity of the concentration should reach 8×10 -5 M is a qualified sample.

[0048] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative work on the basis of the technical solution disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a lead ion fluorescence detection tool, characterized in that: include: Will be able to and Pb 2+ A ligand containing CH3NH3Br or CsBr that reacts to form perovskite and exhibits photoluminescence properties is used to prepare a lead ion fluorescence detection tool on different substrates; wherein the lead ion fluorescence detection tool is a CH3NH3Br fluorescence detection film, a CsBr fluorescence detection film or a CsBr fluorescence detection test paper; (1) preparing a CH3NH3Br fluorescence detection film, comprising: A CH3NH3Br powder with a purity of more than 99.9% was selected and mixed with N,N-dimethylformamide to prepare a CH3NH3Br saturated solution with a concentration of 3M; the solute was evenly mixed by magnetic stirring for 10-15 minutes; the CH3NH3Br solution was spin-coated on a glass slide substrate in air to obtain a film with high enrichment of CH3NH3Br; wherein, the CH3NH3Br solution was spin-coated using a desktop coating machine, the spin-coating speed was controlled at 5000rpm, the spin-coating time was 30s, and the film was uniform and dense; (2) Preparing a CsBr fluorescence detection film or a CsBr fluorescence detection test paper, comprising: Select CsBr powder with a purity of more than 99.9% and spread it evenly on the bottom of the molybdenum boat. Select a glass slide or wax paper and fix it on the substrate above the molybdenum boat in the evaporation chamber. Put down the bell jar and evacuate the evaporation reaction chamber to a vacuum degree of 2×10 -3 Pa or more; set the substrate rotation speed to 5r / min, the evaporation current to 90A for evaporation experiment, and the evaporation time to 5min to obtain a CsBr highly enriched and dense fluorescence detection film or fluorescence detection test paper; wherein the thickness of the CsBr fluorescence detection film is 400-500nm; When the prepared lead ion fluorescence detection tool is used, a solution containing lead ions is titrated onto the prepared fluorescence detection tool to generate a sample, and the lead ion concentration is determined according to the change in the fluorescence intensity of the sample. The fluorescence peak of the CH3NH3Br detection film is located at 532nm, and the fluorescence peak of the CsBr detection film and the test paper is located at 515nm. The fluorescence of the detection samples is green; the CH3NH3Br film has a good fluorescence intensity for Pb 2+ The detection sensitivity of the concentration reached 1×10 -4 M, CsBr detection film for Pb 2+ The detection sensitivity of the concentration reached 1.6×10 -5 M, CsBr test paper for Pb 2+ The detection sensitivity of the concentration reached 8×10 -5 M.

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