A microneedle array detector for methyl iodide gas detection

Abstract

The present invention provides a microneedle array detector for methyl iodide gas detection, which is prepared by the following method: S1, preparing Pb-anchored mesoporous glass photocurable ink by a sol-gel method; S2, preparing a Pb-anchored mesoporous glass microneedle array; S3, preparing a perovskite mesoporous glass composite microneedle array; S4, integrating the perovskite mesoporous glass composite microneedle array with a blue light LED chip for methyl iodide detection. The present invention provides a microneedle array detector for methyl iodide gas detection, which realizes high-sensitivity detection of methyl iodide gas, and has the advantages of short response time, high reliability, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of methyl iodide gas detection, and in particular relates to a microneedle array detector for methyl iodide gas detection. Background Art

[0002] Methyl iodide is an excellent refrigerant, solvent and propellant, and has been widely used. However, methyl iodide has certain biological toxicity, and when exposed to ultraviolet light at high altitude, it will release iodine atoms, which will damage the ozone layer, so it has attracted widespread attention. However, there is currently no portable, fast and accurate method to detect the presence of methyl iodide. In recent years, perovskite materials have attracted much attention due to their simple synthesis and unique optical properties. However, there are still some problems in the practical application of perovskite materials, such as: sensitivity to humidity, heat and light, resulting in poor stability; traditional perovskite synthesis processes rely on toxic organic solvents, which are harmful to human health and the environment. In the existing perovskite mesoporous glass process, a two-step method is often used to confine the growth of perovskite quantum dots in the mesoporous channel, that is, firstly, the mesoporous glass is immersed in a lead halide PbX2 precursor solution and vacuum dried to remove excess solvent, and then immersed in a cesium halide CsX precursor solution. The above two-step method will inevitably cause lead halide PbX2 to remain on the surface during the vacuum drying process to remove the solvent and form large-sized nanocrystals with cesium halide CsX, which will block the pores to a certain extent, thereby affecting the ion exchange process between gas perovskite and halogen ions. The effect of residual perovskite quantum dots on the glass surface is not obvious in liquid detection, but in gas detection, the detection rate and detection accuracy will be greatly affected because the large-sized perovskite nanocrystals remaining on the surface have a small specific surface area and will block the pores. Therefore, it is urgent to develop a new method to avoid the formation of perovskite quantum dots on the surface of mesoporous glass.

[0003] In addition, the current perovskite mesoporous glass is still a sheet structure, and microneedle technology can significantly improve the sensitivity in gas detection, which mainly increases the capture rate and reaction speed of gas molecules by increasing the contact area and enhancing the diffusion effect. In addition, the design of microneedles can optimize surface reactivity and reduce the detection limit, thereby maintaining good detection capabilities at low concentrations. At the same time, the integrated design of microneedle sensors enables them to be combined with other sensor systems to further improve the accuracy and sensitivity of detection. However, current methods still cannot achieve the manufacture of complex structures such as microneedle arrays. Summary of the invention

[0004] The purpose of the present invention is to provide a microneedle array detector for methyl iodide gas detection in view of the problems in the prior art.

[0005] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0006] A microneedle array detector for methyl iodide gas detection, characterized in that the detector is prepared by the following method:

[0007] S1, Pb-anchored mesoporous glass photocurable ink was prepared by sol-gel method, organic aluminum salt was weighed and dissolved in 5 mL of deionized water, tetraethyl orthosilicate was slowly added to form a mixed solution, in which the molar ratio of aluminum to silicon was 0.1:99.9-10:90, concentrated nitric acid solution was added to adjust the pH value of the mixed solution to between 3.0 and 4.0 to promote the hydrolysis of tetraethyl orthosilicate, silane coupling agent and photoinitiator were added after stirring, and after stirring for 8-10 h, a lead source was introduced, and the molar ratio of lead to silicon was 0.1%-5%;

[0008] S2, dropping the prepared Pb-anchored mesoporous glass photocurable ink onto the photocuring platform of the DLP printer to perform 3D printing, and drying and sintering the printed microneedle array to obtain a Pb-anchored mesoporous glass microneedle array, wherein the Pb-anchored mesoporous glass microneedle array includes a photocured integrally formed bottom plate and a microneedle structure, each microneedle structure array is distributed on the bottom plate, and a number of nanoscale mesoporous channels are evenly distributed on each microneedle structure;

[0009] S3, dissolving cesium halide CsX in water at a concentration of 0.3-1.5 g / ml, fully dissolving after magnetic stirring to form a precursor solution, immersing Pb-anchored mesoporous glass in cesium bromide CsBr precursor, and the Pb ions anchored in the mesoporous glass channel react and generate separated nanoscale perovskite quantum dots through nano-confinement, and soaking for 1-5 minutes. After soaking, taking out the perovskite mesoporous glass microneedle array, removing the residual cesium halide CsX precursor on the surface, and completely volatilizing the solvent in the mesoporous channel of the perovskite mesoporous glass microneedle array at room temperature to form a perovskite mesoporous glass composite material microneedle array;

[0010] S4, integration of perovskite mesoporous glass composite microneedle array with blue LED chip for methyl iodide detection.

[0011] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0012] As a preferred technical solution of the present invention: the preparation process of Pb-anchored mesoporous glass photocurable ink uses nitric acid and ammonia water to adjust the pH value to control the gelation process.

[0013] As a preferred technical solution of the present invention: the organic aluminum salt is aluminum lactate.

[0014] As a preferred technical solution of the present invention: in step S2, the drying and sintering steps of the printed mesoporous glass microneedle array are as follows: placing it in a 50°C oven for 48 hours, and continuously heating the obtained transparent block dry gel at 100°C for 24 hours; then sintering the dry gel from 100°C to 600°C, heating at a rate of 1°Cmin; the dry gel removes the lactic acid groups in the glass at above 400°C to form mesopores with uniform pore size of 3nm~8nm, and keeping warm at 600°C until it is converted into a Pb-anchored mesoporous glass microneedle array.

[0015] As a preferred technical solution of the present invention: in step S2, in the Pb-anchored mesoporous glass microneedle array, each microneedle structure is arranged in 4 rows and 4 columns, the needle tip accuracy of the microneedle structure is 64um, and the spacing between each microneedle structure is 500um.

[0016] As a preferred technical solution of the present invention: the lead source is lead acetate Pb (Ac) 2 solution.

[0017] Compared with the prior art, the present invention is a microneedle array detector for methyl iodide gas detection. Pb-anchored mesoporous glass photocurable ink is prepared based on the sol-gel method, aluminum lactate and lead acetate are added to realize the anchoring of lead ions in the mesoporous channel, and the Pb-anchored mesoporous glass microneedle array is obtained after DLP 3D printing and sintering. The Pb-anchored mesoporous glass microneedle array is directly immersed in a CsBr precursor, and the Pb ions anchored in the mesoporous channel react with the CsBr precursor and grow in situ to form perovskite quantum dots. The perovskite mesoporous glass composite material microneedle array prepared by the one-step method solves the problem of residual perovskite quantum dots on the surface, thereby solving the detection error problem caused by this. The absence of residual perovskite quantum dots on the surface avoids the problem of low gas detection sensitivity and long response time caused by the residual perovskite quantum dots on the surface of the mesoporous glass microneedle caused by the two-step method.

[0018] The present invention discloses a microneedle array detector for detecting methyl iodide gas. The detector uses a Pb-anchored mesoporous glass microneedle array in combination with perovskite quantum dots, thereby solving the problem of residual perovskite quantum dots on the surface of the microneedle array. The high specific surface area and porous structure of the mesoporous glass microneedle array are utilized to increase the adsorption amount of gas molecules and improve the detection sensitivity. The rich active sites provided by the mesoporous structure are combined to make it easier for methyl iodide gas to interact with the surface of the mesoporous glass microneedle array during detection, thereby improving the adsorption performance of the detector. The uniform nanopores of the mesoporous glass are utilized to separate each perovskite quantum dot, thereby effectively preventing the agglomeration of the perovskite quantum dots, helping to maintain the optical properties and stability of the perovskite quantum dots, and thus improving the accuracy and reliability of gas detection. By combining the luminescence and ion exchange characteristics of the perovskite quantum dots, the luminescence response in the mesoporous glass microneedle array structure reduces the influence of external factors, thereby realizing high-sensitivity detection of methyl iodide gas. In the present invention, the mesoporous glass microneedle array is combined with the perovskite quantum dots to realize rapid response and high-precision detection of methyl iodide gas.

[0019] At the same time, the 3D printing in the present invention is an additive manufacturing technology. The use of DLP 3D printing technology can greatly improve the processing freedom of perovskite mesoporous glass, and at the same time, the accuracy and stability of the overall structure prepared are better. Combined with the large specific surface area of ​​the microneedle array, it is more suitable for precision detection scenarios. At the same time, the use of environmentally friendly solvents - water replaces the traditional perovskite synthesis process that relies on toxic organic solvents, which improves the solubility of the precursor while greatly reducing the production cost, making the mesoporous glass microneedle array detector very promising. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of 3D printed Pb-anchored mesoporous glass microneedle array;

[0021] Figure 2 Transmission electron microscope image of perovskite mesoporous glass;

[0022] Figure 3 This is the luminescence spectrum of the perovskite mesoporous glass composite microneedle array when it is not used for methyl iodide gas detection;

[0023] Figure 4 Luminescence spectra of perovskite mesoporous glass composite microneedle arrays after methyl iodide gas detection. DETAILED DESCRIPTION

[0024] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] Methyl iodide is a methyl halide compound widely used as a methylating agent in organic synthesis. Due to its high reactivity, it can also be used as a fumigant, fungicide, herbicide, pesticide and soil disinfectant. The main sources of methyl iodide in the atmosphere are the production of marine phytoplankton and algae, the emission of nuclear waste gas, and the leakage of the above uses. This can lead to ozone depletion in the troposphere and ozone layer. Worse still, due to its high reactivity with nucleophilic molecules in organisms, inhalation of methyl iodide may induce the risk of mutation and carcinogenesis.

[0026] However, due to the colorless and odorless characteristics of methyl iodide, there is currently no simple way to detect the presence of methyl iodide. Based on this, the present invention proposes a perovskite mesoporous glass probe for methyl iodide detection, which adsorbs a perovskite precursor material solution into the mesoporous structure of a 3D-printed mesoporous glass probe, and obtains a perovskite mesoporous glass composite material microneedle array through vacuum annealing.

[0027] A microneedle array detector for methyl iodide gas detection, the detector is prepared by the following method:

[0028] S1, Pb-anchored mesoporous glass photocurable ink was prepared by sol-gel method, organic aluminum salt was weighed and dissolved in 5 mL of deionized water, tetraethyl orthosilicate was slowly added to form a mixed solution, in which the molar ratio of aluminum to silicon was 0.1:99.9-10:90, concentrated nitric acid solution was added to adjust the pH value of the mixed solution to between 3.0 and 4.0, silane coupling agent and photoinitiator were added after stirring, and after stirring for 8-10 h, a lead source was introduced, and the molar ratio of lead to silicon was 0.1%-5%;

[0029] S2, dropping the prepared Pb-anchored mesoporous glass photocurable ink onto the photocuring platform of the DLP printer for 3D printing, and drying and sintering the printed microneedle array to obtain a Pb-anchored mesoporous glass microneedle array;

[0030] S3, dissolving cesium halide CsX in water at a concentration of 0.3-1.5 g / ml, fully dissolving after magnetic stirring to form a precursor solution, immersing the perovskite mesoporous glass microneedle array in the precursor solution for 1-5 minutes, and after immersion, taking out the perovskite mesoporous glass microneedle array, removing the residual cesium halide CsX precursor on the surface, and completely volatilizing the solvent in the mesoporous channel of the perovskite mesoporous glass microneedle array at room temperature to form a perovskite mesoporous glass composite material microneedle array;

[0031] S4, integration of perovskite mesoporous glass composite microneedle array with blue LED chip for methyl iodide detection.

[0032] In step S1, the Pb-anchored mesoporous glass photocurable ink preparation process uses nitric acid and ammonia water to adjust the pH value to control the gelation process.

[0033] In step S1, the organic aluminum salt is aluminum lactate.

[0034] In step S2, the drying and sintering steps of the printed microneedle array are as follows: placing the obtained transparent block dry gel in a 50°C oven for 48 hours, heating the obtained transparent block dry gel at 100°C for 24 hours; then sintering the dry gel from 100°C to 600°C at a rate of 1°C min -1 The temperature was raised at a rate of 100 °C; the dry gel removed the lactic acid groups in the glass at above 400 °C to form mesopores with uniform pore sizes of 3 nm to 8 nm, and was then kept at 600 °C for several hours to convert into a Pb-anchored mesoporous glass microneedle array.

[0035] In step S2, the Pb-anchored mesoporous glass microneedle array is arranged in 4 rows and 4 columns, the microneedle spacing is 500um, and the needle tip accuracy is 64um.

[0036] The lead source is lead acetate Pb (Ac) 2 solution.

[0037] Among them, Pb-anchored mesoporous glass photocurable ink is a photocurable material that combines lead anchoring technology and the properties of mesoporous glass.

[0038] DLP refers to Digital Light Processing technology.

[0039] The innovation of the present invention is that Pb-anchored mesoporous glass is developed based on the sol-gel method, which avoids the residual perovskite quantum dots on the surface, and based on this, Pb-anchored mesoporous glass photocurable ink is developed, and micro-needle arrays of perovskite mesoporous glass with micron-level precision are manufactured using DLP 3D printing technology, which greatly improves the processing freedom of perovskite mesoporous glass. The microneedle array has a large specific surface area and is more suitable for precision detection scenarios. At the same time, the use of a conformal solvent - water replaces the toxic organic solvents that are dependent on the traditional perovskite synthesis process, which improves the solubility of the precursor while greatly reducing the production cost, which is more conducive to the commercial application of mesoporous glass microneedle array detectors.

[0040] The specific invention points are as follows:

[0041] 1. The present invention adopts the sol-gel method to prepare a Pb-anchored mesoporous glass microneedle array with a mesopore size distribution of 3 to 8 nm, thereby avoiding the PbX2 precursor remaining on the surface of the mesoporous glass, thereby reducing the residual perovskite quantum dots on the glass surface. Since the mesoporous glass has the characteristics of large specific surface area, it has strong adsorption and enrichment effects on gas molecules. In addition, the microneedle array can increase the contact area and enhance the diffusion effect to improve the capture rate and reaction speed of gas molecules. The design of the microneedle can optimize the surface reaction activity and reduce the detection limit, thereby maintaining good detection capabilities at low concentrations. Therefore, the mesoporous glass is combined with the microneedle array, and the anion exchange principle can be used to realize the rapid detection of methyl iodide gas.

[0042] 2. Based on Pb-anchored mesoporous glass gel, Pb-anchored mesoporous glass photocurable ink was developed, and perovskite mesoporous glass microneedle arrays with micron-level precision were manufactured using digital light processing (DLP) 3D printing technology, such as Figure 1 shown.

[0043] 3. The present invention uses water as a solvent to replace the traditional perovskite synthesis process that relies on toxic organic solvents to prepare the perovskite precursor, that is, cesium halide (CsX) is dissolved in water at a concentration of 0.3-1.5g / ml, and magnetic stirring is used to fully dissolve. The mesoporous glass is immersed in the precursor solution for 1-5 minutes. After the immersion is completed, the mesoporous glass is taken out, the residual cesium halide (CsX) precursor on the surface is removed, and the solvent in the mesoporous glass is completely volatilized at room temperature.

[0044] 4. Integrate the 3D printed perovskite mesoporous glass composite microneedle array with a blue LED chip. Place the methyl iodide detector in a closed gas chamber containing methyl iodide and observe the change in luminescent color. In practical applications, by comparing the luminescent color changes before and after, it can be determined whether the gas to be tested contains methyl iodide.

[0045] Therefore, it is of great significance to use new environmentally friendly solvents such as water or low-toxic solvents in the present invention. In addition, the solvent used in the synthesis process also affects the production cost, and the selection of low-cost solvents helps to achieve large-scale commercialization of perovskite detection devices. In the present invention, mesoporous glass is used as a carrier of perovskite, based on the basic principle of anion exchange, that is, when the halogen component of metal halide perovskite changes, its band gap will also change accordingly, and rapid ion exchange is suitable for application scenarios of gas detection.

[0046] The microneedle array detector manufactured by combining 3D printing technology in the present invention has higher sensitivity and rapid response capability, and can realize accurate detection of tiny signals. 3D printing technology can produce mechanical parts with complex geometric structures and optimized functions, which shows that it has wide application potential in modern industry. The microneedle array detector manufactured by combining 3D printing technology has higher sensitivity and rapid response capability, and can realize accurate detection of tiny signals. In the existing research, the field of 3D printing mesoporous glass is still blank, which limits the accuracy and flexibility of the detectors made on this basis.

[0047] The present invention creatively introduces the Pb element when making the mesoporous glass microneedle array by the sol-gel method, and prepares the perovskite mesoporous glass microneedle array by a one-step method, avoiding the PbX2 residue on the mesoporous glass surface, thereby reducing the residual perovskite quantum dots on the glass surface, greatly accelerating the AER rate and detection response time. In addition, the manufacture of single-photon 3D printed mesoporous glass microneedle arrays with micron-level precision is achieved through 3D printing technology, and the PL spectrum shift caused by the ion exchange between perovskite and halogen ions is used to achieve high-sensitivity detection of methyl iodide gas, while having the advantages of short response time and high reliability. Example 1

[0048] Experimental materials: cesium bromide, water, mesoporous glass microneedle array

[0049] Experimental method: Dissolve 1g of cesium bromide in 1ml of deionized water, stir magnetically for 30 minutes at room temperature to fully dissolve it, and obtain a cesium bromide precursor solution. Immerse the mesoporous glass microneedle array in the cesium bromide precursor solution for 1-5 minutes. Take it out after soaking, and immerse it in the mesoporous glass microneedle array, wipe off the residual precursor on the surface, and completely evaporate the solvent in the mesoporous glass channel at room temperature to obtain a perovskite mesoporous glass composite material microneedle array. Bond it to the blue light LED chip, place the detector in a closed gas chamber containing methyl iodide, and observe the change in luminescent color. Change the detection concentration to obtain the minimum response concentration of the microneedle array.

[0050] Experimental results: After drying, the perovskite mesoporous glass was tested by transmission electron microscopy (TEM). It can be seen that after filling with perovskite, there are obvious perovskite nanocrystals in the mesoporous glass, such as Figure 2 As shown. Under the excitation of blue LED, it emits blue-green light. Its photoluminescence spectrum is measured. Before the reaction, its emission peak is at 496 nanometers, as shown Figure 3As shown. After the perovskite mesoporous glass composite microneedle array was placed in a sealed air chamber filled with methyl iodide for 2 seconds, the perovskite mesoporous microneedle array emitted red light under the excitation of a blue LED. After the microneedle array was placed in a sealed air chamber filled with methyl iodide for 2 seconds, it emitted red light under the excitation of a blue LED. Its photoluminescence spectrum was measured. After the reaction, the emission peak shifted to 635 nanometers, as shown. Figure 4 shown.

[0051] In existing studies, the lower detection limit of iodomethane gas detector is 164.15μmol / m³, that is, iodine ion (I - ) equivalent to 164.15 ppm. The low detection limit of the microneedle array detector made by the method of the present invention can reach 5 ppm, which greatly improves the detection limit.

[0052] The above-mentioned specific implementation methods are used to explain the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A microneedle array detector for methyl iodide gas detection, characterized in that: The detector is prepared by the following method: S1, preparing Pb-anchored mesoporous glass photocurable ink by sol-gel method, weighing organic aluminum salt and dissolving it in 5 mL of deionized water, slowly adding tetraethyl orthosilicate to form a mixed solution, in which the molar ratio of aluminum to silicon is 0.1:99.9-10:90, adding concentrated nitric acid solution to adjust the pH value of the mixed solution to between 3.0 and 4.0 to promote the hydrolysis of tetraethyl orthosilicate, adding silane coupling agent and photoinitiator after stirring, and introducing lead source after stirring for 8 to 10 hours, and the molar ratio of lead to silicon is 0.1%-5%; S2, dropping the prepared Pb-anchored mesoporous glass photocurable ink onto the photocuring platform of the DLP printer to perform 3D printing, and drying and sintering the printed microneedle array to obtain a Pb-anchored mesoporous glass microneedle array, wherein the Pb-anchored mesoporous glass microneedle array includes a photocured integrally formed bottom plate and a microneedle structure, each microneedle structure array is distributed on the bottom plate, and a number of nanoscale mesoporous channels are evenly distributed on each microneedle structure; S3, dissolving CsBr in water at a concentration of 0.3-1.5 g / ml, fully dissolving after magnetic stirring to form a precursor solution, immersing Pb-anchored mesoporous glass in the CsBr precursor, allowing the Pb ions anchored in the mesoporous channels to react and generate separated nanoscale perovskite quantum dots through nanoconfinement, and soaking for 1-5 minutes. After soaking, taking out the perovskite mesoporous glass microneedle array, removing the residual CsBr precursor on the surface, and completely volatilizing the solvent in the mesoporous channels of the perovskite mesoporous glass microneedle array at room temperature to form a perovskite mesoporous glass composite material microneedle array; S4, integration of perovskite mesoporous glass composite microneedle array with blue LED chip for methyl iodide detection.

2. The microneedle array detector for methyl iodide gas detection according to claim 1, characterized in that: In step S1, the Pb-anchored mesoporous glass photocurable ink preparation process uses nitric acid and ammonia water to adjust the pH value to control the gelation process.

3. The microneedle array detector for methyl iodide gas detection according to claim 1, characterized in that: In step S1, the organic aluminum salt is aluminum lactate.

4. The microneedle array detector for methyl iodide gas detection according to claim 1, characterized in that: In step S2, the drying and sintering steps of the printed mesoporous glass microneedle array are as follows: placing it in a 50°C oven for 48 hours, and continuously heating the obtained transparent block dry gel at 100°C for 24 hours; then sintering the dry gel from 100°C to 600°C, heating at a rate of 1°C min; the dry gel removes the lactic acid groups in the glass at above 400°C to form mesopores with uniform pore size of 3nm to 8nm, and keeps warm at 600°C until it is converted into a Pb-anchored mesoporous glass microneedle array.

5. The microneedle array detector for methyl iodide gas detection according to claim 1, characterized in that: In step S2, in the Pb-anchored mesoporous glass microneedle array, each microneedle structure is arranged in 4 rows and 4 columns, the needle tip accuracy of the microneedle structure is 64 um, and the spacing between each microneedle structure is 500 um.

6. The microneedle array detector for methyl iodide gas detection according to claim 1, characterized in that: The lead source is lead acetate Pb(Ac)2 solution.

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