Preparation method of high-concentration ammonia gas sensor

Abstract

The invention discloses a preparation method of a high-concentration ammonia gas sensor. The preparation method comprises the following steps: step 1, preparing a solution a containing a perovskite precursor I; 2, preparing a solution b containing a perovskite precursor II; 3, 3-aminopropyltriethoxysilane is added into the solution b, standing is carried out, and a solution c is obtained; step 4, dripping the solution c into a sample adding area on the surface of the paper base, and then dripping the solution a into the sample adding area on the surface of the paper base to obtain a SiO2-coated perovskite nanocrystalline paper base; and step 5, enabling the paper base containing the SiO2 coated perovskite nanocrystalline to be in contact with ammonia gas, and detecting the concentration of the ammonia gas. According to the prepared high-concentration ammonia gas sensor, the application range of the perovskite nanocrystals is expanded, and the preparation method is simple, rapid and low in cost.

Description

Technical Field

[0001] The present application relates to a method for preparing a high-concentration ammonia sensor, and belongs to the field of nanomaterial application. Background Art

[0002] Perovskite nanomaterials have attracted people's attention and research due to their excellent optoelectronic properties. Perovskite nanomaterials have the advantages of high fluorescence quantum efficiency (PLQY), wide adjustable emission wavelength range, excellent photoelectric transmission performance, simple synthesis and low cost, and have good application prospects in optoelectronic devices and sensing fields.

[0003] As a carrier, paper can give perovskite a wider and more convenient application, such as using it to build paper-based sensors, thereby greatly shortening the detection time and developing user-friendly portable sensors for online monitoring. However, perovskite is greatly affected by the environment and has poor stability, so stability has always been a problem that perovskite nanocrystals need to solve, and it is also the biggest obstacle to its commercialization.

[0004] In order to improve the stability of perovskite in the environment, doping, polymer encapsulation, silicon dioxide (SiO2) wrapping, etc. have been reported. Among them, SiO2 is a commonly used method to stabilize perovskite in the preparation of perovskite LEDs. Perovskite nanocrystals are usually embedded in a SiO2 matrix formed by silane hydrolysis, so that the obtained SiO2-coated perovskite nanocrystals can maintain long-term stability in the air and have a high fluorescence quantum yield, and can also improve resistance to polar substances, such as ammonia.

[0005] In the event of an ammonia leak, timely and accurate detection and location of the leak are critical to emergency response. Ammonia leaks can cause pollution and harm to the environment. The release of high concentrations of ammonia can lead to contamination of soil and water bodies and harm to plants and organisms. Through ammonia detection, ammonia leaks can be detected in time, measures can be taken to limit the spread of ammonia and appropriate treatment can be carried out to protect the environment from ammonia pollution. In the event of an ammonia leak, according to the Chemical Hazard Protection Guide, protection against low levels of ammonia can be provided by using a respirator with an appropriate ammonia filter canister, while high levels of ammonia require the use of a self-contained breathing apparatus. Therefore, fast ammonia sensors are needed to accurately determine the required personal protective equipment to provide appropriate protection. Most of the ammonia sensors currently reported have a full-scale range of up to 100ppm, which cannot meet the range required to make appropriate personal protective equipment decisions in high concentration situations. In addition, these sensors will quickly deplete when there is a large amount of ammonia leak and cannot be used to help locate the leak. In these cases, sensors for high-concentration ammonia detection can provide an accurate, reliable and cost-effective method to make appropriate personal protective equipment decisions. Summary of the invention

[0006] The purpose of this application is to make up for the shortcomings of existing detection methods and propose a method for preparing a high-concentration ammonia sensor based on perovskite nanocrystals.

[0007] According to one aspect of the present application, a method for preparing a high-concentration ammonia sensor is provided, the preparation method comprising the following steps:

[0008] Step 1: preparing a solution a containing a perovskite precursor I;

[0009] Step 2: preparing a solution b containing a perovskite precursor II;

[0010] Step 3: Add 3-aminopropyltriethoxysilane to solution b and let stand to obtain solution c;

[0011] Step 4: dripping solution c onto the sample adding area on the surface of the paper base, and then dripping solution a onto the sample adding area on the surface of the paper base, to obtain a paper base containing SiO2-coated perovskite nanocrystals;

[0012] Wherein, the perovskite precursor I is selected from Cs2CO3 and / or MABr;

[0013] The perovskite precursor II is selected from at least one of PbBr2, PbI2, and PbCl2.

[0014] Optionally, the concentration of the perovskite precursor I in the solution a is 0.05-0.2 mmol / L.

[0015] Optionally, the concentration of the perovskite precursor I in the solution a is any value among 0.05 mmol / L, 0.1 mmol / L, 0.15 mmol / L, 0.2 mmol / L, or a range therebetween.

[0016] Optionally, the concentration of the perovskite precursor II in the solution b is 0.05-0.2 mmol / L.

[0017] Optionally, the concentration of the perovskite precursor II in the solution b is any value of 0.05 mmol / L, 0.1 mmol / L, 0.15 mmol / L, 0.2 mmol / L, or a range between two values.

[0018] Optionally, the volume fraction of 3-aminopropyltriethoxysilane in the solution c is 0% to 10%.

[0019] Optionally, the volume fraction of 3-aminopropyltriethoxysilane in the solution c is any value of 0%, 3%, 5%, 7%, 10%, or a range between two values.

[0020] Optionally, in step 4, the volume ratio of solution a to solution c is 1:0.1-10.

[0021] Optionally, the volume ratio of solution a to solution c is any value of 1:0.1, 1:1, 1:3, 1:5, 1:7, 1:9, 1:10, or a range value between two values.

[0022] Optionally, in step 3, the standing time is 5 min to 12 h.

[0023] Optionally, in step 3, the standing time is any value of 5 min, 10 min, 20 min, 30 min, 40 min, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 min, or a range between two values.

[0024] Optionally, the paper substrate is selected from at least one of filter paper, nitrocellulose membrane, and polyvinylidene fluoride membrane.

[0025] According to another aspect of the present application, there is provided an application of a high-concentration ammonia sensor prepared by the preparation method described above in ammonia detection.

[0026] The beneficial effects of this application include:

[0027] 1) The preparation method provided in this application is a novel, simple, fast and low-cost preparation method, and the prepared sensor has a wider detection range of ammonia, and the experimental results are clear and intuitive.

[0028] 2) The preparation method provided in this application has expanded the application scope of perovskite nanocrystals and provided a new basis for the application of perovskite nanocrystals in sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a graph showing the change in fluorescence intensity after Example 1 of the present application came into contact with ammonia.

[0030] Figure 2 This is a graph showing the change in fluorescence intensity after Example 2 of the present application came into contact with ammonia.

[0031] Figure 3 This is a graph showing the change in fluorescence intensity after Example 3 of the present application came into contact with ammonia. DETAILED DESCRIPTION

[0032] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0033] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0034] Example 1

[0035] Prepare 0.1mmol / L Cs2CO3 solution, prepare 0.1mmol / L PbBr2 solution, add 3-aminopropyltriethoxysilane (APTES) to the PbBr2 solution, and let it stand. The volume fraction of APTES added is 3%; the standing time is 60 minutes;

[0036] 1 μL of the mixed solution of APTES and PbBr2 was pipetted and dropped on the surface of the polyvinylidene fluoride (PVDF) membrane, and then 2 μL of Cs2CO3 solution was pipetted and dropped on the surface of the polyvinylidene fluoride (PVDF) membrane paper substrate at the same position.

[0037] Fluorescence intensity diagram Figure 1 As shown, compared with other volatile gases, the sensor has a significant decrease in fluorescence intensity after being exposed to 2500ppm ammonia for 1 minute.

[0038] Example 2

[0039] Prepare 0.09mmol / L Cs2CO3 solution, prepare 0.09mmol / L PbBr2 solution, add APTES to the PbBr2 solution, and let it stand. The volume fraction of APTES added is 1%; the standing time is 10 hours;

[0040] 1 μL of the mixed solution of APTES and PbBr2 was pipetted and dropped on the surface of the PVDF membrane, and then 2 μL of Cs2CO3 solution was pipetted and dropped on the paper substrate surface at the same position.

[0041] like Figure 2 As shown, after the sensor was in contact with 2000-4000 ppm ammonia for 1 minute, the fluorescence intensity gradually decreased with the increase of ammonia concentration.

[0042] Example 3

[0043] Prepare 0.2mmol / L Cs2CO3 solution, prepare 0.15mmol / L PbBr2 solution, add APTES to the PbBr2 solution, and let it stand. The volume fraction of APTES added is 5%; the standing time is 30 minutes;

[0044] 1 μL of the mixed solution of APTES and PbBr2 was dripped on the surface of the PVDF membrane, and then 2 μL of Cs2CO3 solution was dripped on the paper substrate surface at the same position;

[0045] according to Figure 3 It can be seen that after the sensor was in contact with 2000-3600 ppm ammonia for 1 minute, the fluorescence intensity gradually decreased with the increase of ammonia concentration.

[0046] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a high concentration ammonia sensor, characterized in that: The preparation method comprises the following steps: Step 1: preparing a solution a containing a perovskite precursor I; Step 2: preparing a solution b containing a perovskite precursor II; Step 3: Add 3-aminopropyltriethoxysilane to solution b and let stand to obtain solution c; Step 4: dripping solution c onto the sample adding area on the surface of the paper base, and then dripping solution a onto the sample adding area on the surface of the paper base, to obtain a paper base containing SiO2-coated perovskite nanocrystals; Wherein, the perovskite precursor I is selected from Cs2CO3 and / or MABr; The perovskite precursor II is selected from at least one of PbBr2, PbI2, and PbCl2.

2. The preparation method according to claim 1, characterized in that: The concentration of the perovskite precursor I in the solution a is 0.05-0.2 mmol / L.

3. The preparation method according to claim 1, characterized in that: The concentration of the perovskite precursor II in the solution b is 0.05-0.2 mmol / L.

4. The preparation method according to claim 1, characterized in that: The volume fraction of 3-aminopropyltriethoxysilane in the solution c is 0% to 10%.

5. The preparation method according to claim 1, characterized in that: In step 4, the volume ratio of solution a to solution c is 1:0.1-10.

6. The preparation method according to claim 1, characterized in that: In the step 3, the standing time is 5 minutes to 12 hours.

7. The preparation method according to claim 1, characterized in that: The paper base is selected from at least one of filter paper, nitrocellulose membrane and polyvinylidene fluoride membrane.

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