Preparation method of stannic oxide-stannic sulfide-silicon dioxide-based rhodamine 6G fluorescent film sensor for rapidly detecting NO2
By preparing a tin dioxide-tin disulfide-silica-based rhodamine 6G fluorescent thin film sensor, the problems of insufficient sensor sensitivity and selectivity were solved, and rapid and specific NO2 gas detection was achieved, which is suitable for nitrate explosives production workshops and storage rooms.
Patent Information
- Application Number
- CN202510803228.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-09-23
AI Technical Summary
The film formation method of existing fluorescent thin film sensors will greatly reduce the sensitivity, making it impossible to quickly detect ultra-low concentration NO2 gas, and lack specificity in complex gas environments.
The preparation method of tin dioxide-tin disulfide-silica-based rhodamine 6G fluorescent thin film sensor is adopted. Sn(OH)4-SiO2 nanospheres are pyrolyzed and thermally sulfurized under nitrogen purge and high temperature conditions to form SnO2-SnS2-SiO2 nanospheres, which are then combined with rhodamine 6G probe molecules to form a heterojunction, thereby achieving specific adsorption and fluorescence quenching of NO2.
The sensitivity and selectivity of the sensor were improved, the detection time was optimized from 60min to 2min, and the lower limit of detection concentration was optimized from 100ppm to 10ppb, making it suitable for specific detection of NO2 gas in complex environments.
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Figure CN120681783A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a fluorescent thin film sensor. Background Art
[0002] Under normal conditions, rapid detection and monitoring of NO2 is of great significance in areas such as safety inspections in production workshops and storage rooms for nitrate explosives. Currently available resistive sensors require long periods of uninterrupted power supply, which increases the risk of electric spark detonation in high-density combustible environments. In addition, since the detection mechanism of resistive sensors is based on changes in resistance caused by gas adsorption on semiconductors, their gas selectivity is very poor and cannot meet the requirements of specific sensing in complex gas environments. Fluorescent sensors, on the other hand, can achieve highly selective gas sensing through the screening of probe molecules and the grafting and modification of functional groups, and can achieve contactless light signal collection through the design of the optical path. Among them, the ease of device fabrication and portability of thin-film fluorescent sensors have attracted widespread attention in the field of fluorescent sensing. However, traditional fluorescent thin-film sensors require the participation of organic polymer film-forming agents such as polymethyl methacrylate (PMMA) during the film-forming process. The dense polymer film will cover a large number of probe molecules underneath, significantly reducing the number of effective probe molecules. This greatly reduces the sensitivity of the sensor and makes it impossible to quickly detect ultra-low concentrations of NO2 gas. These factors limit the application scope and field of existing sensors and make them unable to meet the requirements of use in special fields. Summary of the Invention
[0003] The present invention aims to solve the problem that the film forming method of the existing fluorescent thin film sensor will greatly reduce the sensitivity, and further provides a preparation method of a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection.
[0004] A method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection is carried out according to the following steps: 1. Heat deionized water, anhydrous ethanol and ammonia solution and stir until they are evenly mixed and the temperature is stabilized at 30°C to 70°C to obtain a deionized water-anhydrous ethanol-ammonia solution system; Second, at a temperature of 30°C to 70°C, a SnCl2·2H2O / TEOS anhydrous ethanol solution was added dropwise to a deionized water-anhydrous ethanol-ammonia system, and then hydrolyzed at a temperature of 30°C to 70°C for 0.5h to 3h. Finally, the system was centrifuged, washed, and dried to obtain Sn(OH)4-SiO2 nanospheres. 3. Under nitrogen purge conditions, Sn(OH)4-SiO2 nanospheres and sublimed sulfur powder are placed at the gas outlet and gas inlet of a tube furnace, respectively. Then, under nitrogen purge and high temperature conditions, the Sn(OH)4-SiO2 nanospheres are pyrolyzed and thermally sulfurized to obtain SnO2-SnS2-SiO2 nanospheres. Fourth, the SnO2-SnS2-SiO2 nanospheres and the probe molecule Rhodamine 6G were ultrasonically dispersed in a dichloromethane reagent to obtain a mother solution. A quartz plate treated with piranha solution was vertically inserted into the mother solution, and then the quartz plate was slowly pulled upward to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film. 5. The SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film is dried and aged to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film sensor.
[0005] The beneficial effects of the present invention are: The SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film prepared by the present invention has a larger specific surface area than dense organic polymer films, exposing more effective probe molecules, and preliminarily improving the sensitivity of the sensor. Furthermore, the specific adsorption of NO2 by the SnO2 lattice and the effect of the SnO2-SnS2 heterojunction are used to convert NO2 into NO2 that is more easily reacted with the Rhodamine 6G probe molecules. - , NO2 - The nitrosation reaction with the acidic Rhodamine 6G probe molecule quenched its fluorescence, significantly improving the sensor's sensitivity. The sensor's detection time was optimized from 60 minutes to 2 minutes, and its detection limit was reduced from 100 ppm to 10 ppb. Furthermore, the dual selectivity of the SnO2-SnS2 heterojunction and the Rhodamine 6G probe molecule improved the selectivity of the photonic crystal-based fluorescent film, enabling it to meet the specific detection requirements for NO2 gas in complex detection environments, making it suitable for use in specialized areas such as production workshops and storage rooms for nitrate explosives. BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Figure 1 This is a microscopic morphology of Sn(OH)4-SiO2 nanospheres prepared in step 2 of Example 1; Figure 2 This is a digital photo of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; Figure 3 This is a SEM photo of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; Figure 4SEM image of the organic polymer fluorescent thin film sensor prepared for comparative experiment; Figure 5 The fluorescence intensity spectrum of the organic polymer fluorescent film sensor prepared in the comparison experiment before and after the reaction with 10ppm NO2 for 60 minutes; Figure 6 The fluorescence intensity spectrum of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1 before and after the reaction with 10ppm NO2 for 2 minutes; Figure 7 This is a bar graph of experimental data on gas selectivity of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; Figure 8 This is a transmission electron microscope image of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1. DETAILED DESCRIPTION
[0007] Specific embodiment 1: This embodiment is a method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection, which is carried out according to the following steps: 1. Heat deionized water, anhydrous ethanol and ammonia solution and stir until they are evenly mixed and the temperature is stabilized at 30°C to 70°C to obtain a deionized water-anhydrous ethanol-ammonia solution system; Second, at a temperature of 30°C to 70°C, a SnCl2·2H2O / TEOS anhydrous ethanol solution was added dropwise to a deionized water-anhydrous ethanol-ammonia system, and then hydrolyzed at a temperature of 30°C to 70°C for 0.5h to 3h. Finally, the system was centrifuged, washed, and dried to obtain Sn(OH)4-SiO2 nanospheres. 3. Under nitrogen purge conditions, Sn(OH)4-SiO2 nanospheres and sublimed sulfur powder are placed at the gas outlet and gas inlet of a tube furnace, respectively. Then, under nitrogen purge and high temperature conditions, the Sn(OH)4-SiO2 nanospheres are pyrolyzed and thermally sulfurized to obtain SnO2-SnS2-SiO2 nanospheres. Fourth, the SnO2-SnS2-SiO2 nanospheres and the probe molecule Rhodamine 6G were ultrasonically dispersed in a dichloromethane reagent to obtain a mother solution. A quartz plate treated with piranha solution was vertically inserted into the mother solution, and then the quartz plate was slowly pulled upward to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film. 5. The SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film is dried and aged to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film sensor.
[0008] The beneficial effects of this embodiment are: The SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film prepared in this embodiment has a larger specific surface area than dense organic polymer films, exposing more effective probe molecules, and preliminarily improving the sensitivity of the sensor. Furthermore, the specific adsorption of NO2 by the SnO2 lattice and the effect of the SnO2-SnS2 heterojunction are used to convert NO2 into NO2 that is more easily reacted with the Rhodamine 6G probe molecules. - , NO2 - The nitrosation reaction with the acidic Rhodamine 6G probe molecule quenched its fluorescence, significantly improving the sensor's sensitivity. The sensor's detection time was optimized from 60 minutes to 2 minutes, and its detection limit was reduced from 100 ppm to 10 ppb. Furthermore, the dual selectivity of the SnO2-SnS2 heterojunction and the Rhodamine 6G probe molecule improved the selectivity of the photonic crystal-based fluorescent film, enabling it to meet the specific detection requirements for NO2 gas in complex detection environments, making it suitable for use in specialized areas such as production workshops and storage rooms for nitrate explosives.
[0009] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the volume ratio of deionized water to ammonia water in step 1 is (3-15):8; the volume ratio of anhydrous ethanol to ammonia water in step 1 is (50-100):8; and the concentration of ammonia water in step 1 is 25 wt.% to 28 wt.%. Other differences are the same as specific embodiment 1.
[0010] Specific embodiment 3: This embodiment differs from either specific embodiment 1 or 2 in that, in step 1, deionized water, anhydrous ethanol, and aqueous ammonia are heated and stirred at a stirring speed of 100 rpm to 800 rpm and a heating rate of 2°C / min to 10°C / min until they are uniformly mixed and the temperature is stabilized at 30°C to 70°C. Other steps are the same as specific embodiments 1 or 2.
[0011] Specific embodiment 4: This embodiment differs from any one of specific embodiments 1 to 3 in that: the volume ratio of the anhydrous ethanol solution of SnCl2·2H2O / TEOS to the deionized water-anhydrous ethanol-ammonia system described in step 2 is 1:(6-12); the concentration of SnCl2·2H2O in the anhydrous ethanol of the SnCl2·2H2O / TEOS described in step 2 is 0.080 g / mL to 0.016 g / mL, and the concentration of TEOS is 0.177 g / mL to 0.708 g / mL; and the diameter of the Sn(OH)4-SiO2 nanospheres prepared in step 2 is 175 nm to 280 nm. Other aspects are the same as those of specific embodiment 3.
[0012] Specific embodiment 5: This embodiment differs from any one of specific embodiments 1 to 4 in that: in step 2, the anhydrous ethanol solution of SnCl2·2H2O / TEOS is added dropwise to the deionized water-anhydrous ethanol-ammonia system at a temperature of 30°C to 70°C at a dropwise addition rate of 1 mL / min to 5 mL / min; the centrifugation in step 2 is performed at a speed of 6000 r / min to 10000 r / min for 5 to 10 minutes; the washing in step 2 is performed one to three times with ultrapure water and two to four times with anhydrous ethanol; and the drying in step 2 is performed at a temperature of 25°C to 80°C for 4 to 36 hours. Other aspects are the same as specific embodiments 1 to 4.
[0013] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the mass ratio of Sn(OH)4-SiO2 nanospheres to sublimated sulfur powder in step 3 is 1:(0.5-1.5). Other aspects are the same as specific embodiments 1 to 5.
[0014] Specific Embodiment 7: This embodiment differs from Specific Embodiments 1 to 6 in that the nitrogen purge conditions in step 3 are 10 mL / min to 100 mL / min; the pyrolysis and thermal vulcanization in step 3 are specifically performed under nitrogen purge conditions of 10 mL / min to 100 mL / min and a temperature of 350°C to 500°C, and calcined for 15 to 60 minutes. Other embodiments are the same as Specific Embodiments 1 to 6.
[0015] Specific embodiment eight: This embodiment differs from specific embodiments one to seven in that the concentration of SnO2-SnS2-SiO2 nanospheres in the mother solution in step four is 0.020 g / mL to 0.040 g / mL, and the concentration of the probe molecule Rhodamine 6G is 1×10 -2 mol / L~1×10 -7 mol / L; the quartz plate treated with the piranha solution described in step 4 is prepared by completely immersing the quartz plate in the piranha solution for 3 to 12 minutes, removing it and rinsing it with deionized water, and repeating the immersion and rinsing steps 2 to 4 times to obtain the quartz plate treated with the piranha solution; the piranha solution is a mixture of 70 wt.% to 98.3 wt.% concentrated sulfuric acid solution and 3 wt.% to 30 wt.% H2O2 solution in a volume ratio of 1:(0.1 to 1). Other steps are the same as those in Specific Embodiments 1 to 7.
[0016] Specific embodiment 9: This embodiment differs from Specific embodiments 1 to 8 in that: in step 4, the SnO2-SnS2-SiO2 nanospheres and the probe molecule Rhodamine 6G are ultrasonically dispersed in a dichloromethane reagent at a temperature of -10°C to 30°C and a power of 100W to 1500W to obtain a mother liquor; in step 4, the quartz plate is slowly pulled upward at a pulling speed of 0.5mm / h to 2mm / h at a pulling temperature of 25°C to 60°C and a pulling air humidity of 40% to 60%. Other steps are the same as Specific embodiments 1 to 8.
[0017] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the drying and aging in step 5 is carried out at a temperature of 25°C to 120°C for 2h to 16h. Other aspects are the same as specific embodiments 1 to 9.
[0018] The following examples are used to verify the beneficial effects of the present invention: Example 1: A method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection is carried out according to the following steps: 1. Under the conditions of stirring speed of 400 r / min and heating rate of 5°C / min, heat and stir 6 mL of deionized water, 160 mL of anhydrous ethanol and 16 mL of ammonia solution until they are uniformly mixed and the temperature stabilizes at 65°C to obtain a deionized water-anhydrous ethanol-ammonia solution system; The concentration of the ammonia water is 28wt.%; Second, at a temperature of 65°C, a SnCl2·2H2O / TEOS anhydrous ethanol solution was added dropwise to a deionized water-anhydrous ethanol-ammonia system at a dropping rate of 2 mL / min. The solution was then hydrolyzed at 65°C for 2 h, and then centrifuged, washed, and dried to obtain Sn(OH)4-SiO2 nanospheres. The volume ratio of the SnCl2·2H2O / TEOS anhydrous ethanol solution to the deionized water-anhydrous ethanol-ammonia system is 1:9; the concentration of SnCl2·2H2O in the anhydrous ethanol of the SnCl2·2H2O / TEOS is 0.012 g / mL, and the concentration of TEOS is 0.354 g / mL; 3. Under nitrogen purge conditions of 50 mL / min, 2 g of Sn(OH)4-SiO2 nanospheres and 2 g of sublimed sulfur powder were placed at the outlet and inlet of a tube furnace, respectively. Then, under nitrogen purge conditions of 50 mL / min and a temperature of 400°C, the Sn(OH)4-SiO2 nanospheres were calcined for 60 min to obtain SnO2-SnS2-SiO2 nanospheres. Fourth, at a temperature of 0°C and a power of 1000W, SnO2-SnS2-SiO2 nanospheres and the probe molecule Rhodamine 6G were ultrasonically dispersed in a dichloromethane reagent to obtain a mother solution. A quartz plate treated with piranha solution was vertically inserted into the mother solution. Then, at a pulling temperature of 30°C and a pulling air humidity of 40%, the quartz plate was slowly pulled upward at a pulling speed of 0.56mm / h to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film. The concentration of SnO2-SnS2-SiO2 nanospheres in the mother solution is 0.030 g / mL, and the concentration of the probe molecule Rhodamine 6G is 1×10 -4 mol / L; 5. At a temperature of 60°C, the SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film was dried and aged for 12 hours to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film sensor.
[0019] The centrifugation described in step 2 is specifically performed at a speed of 10,000 r / min for 8 minutes; the washing described in step 2 is specifically performed once with ultrapure water and then twice with anhydrous ethanol; the drying described in step 2 is specifically performed at a temperature of 60° C. for 16 hours.
[0020] The average diameter of the Sn(OH)4-SiO2 nanospheres prepared in step 2 is 261 nm.
[0021] The quartz plate treated with the piranha solution described in step 4 is specifically prepared according to the following steps: a quartz plate (20 mm × 10 mm × 1 mm) is completely immersed in the piranha solution for 8 minutes, removed and rinsed with deionized water, and the immersion and rinsing are repeated three times to obtain a quartz plate treated with the piranha solution; the piranha solution is a mixture of 98.3 wt.% concentrated sulfuric acid solution and 30 wt.% H2O2 in a volume ratio of 1:0.43.
[0022] Comparative experiment: Under the conditions of temperature of 0°C and power of 1000W, polymethyl methacrylate and probe molecule rhodamine 6G were ultrasonically dispersed in dichloromethane reagent to obtain a mother solution. The mother solution was coated on a quartz plate (20mm×10mm×1mm) substrate with a coating thickness of 1μm to obtain an organic polymer fluorescent thin film sensor.
[0023] The concentration of polymethyl methacrylate in the mother solution is 5 wt.%, and the concentration of the probe molecule is 1×10 -4 mol / L.
[0024] Figure 1This is a microscopic morphology of Sn(OH)4-SiO2 nanospheres prepared in step 2 of Example 1. As can be seen from the figure, nanospheres with a size of 261 nm were successfully synthesized in step 2 of Example 1.
[0025] Figure 2 This is a digital photo of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; as can be seen from the figure, it appears bright pink.
[0026] Figure 3 This is an SEM photograph of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; as can be seen from the figure, the film is relatively flat, and the nanospheres are basically on the same plane, rather than in a disorderly or piled state.
[0027] Figure 4 This is an SEM photo of the organic polymer fluorescent film sensor prepared in the comparative experiment. As can be seen from the figure, its surface is very dense and smooth. Compared with the film formed by the flat arrangement of nanosphere units, its specific surface area is smaller, the adhesion degree for probe molecules is lower, and the sensitivity of the sensor is reduced.
[0028] Figure 5 The fluorescence intensity spectrum of the organic polymer fluorescent film sensor prepared in the comparison experiment before and after the reaction with 10ppm NO2 for 60 minutes; it can be seen from the figure that even if the detection time is 60 minutes, the fluorescence change rate after the reaction with NO2 is very low.
[0029] Figure 6 This is the fluorescence intensity spectrum of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1 before and after it reacts with 10ppm NO2 for 2 minutes; as can be seen from the figure, it can achieve a high change rate response to NO2 within a detection time of 2 minutes.
[0030] Figure 7 This is a bar chart of the experimental data of the gas selectivity of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; as can be seen from the figure, its response to 100ppm NO2 is much higher than that of other pure concentration gases, confirming its high gas selectivity.
[0031] Figure 8 This is a transmission electron microscope image of the SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1; the lattice structures of SnO2, SnS2 and SnO2-SnS2 heterojunction can be clearly observed in the image, confirming the successful synthesis of each component.
[0032] The SnO2-SnS2-SiO2-based rhodamine 6G fluorescent thin film sensor prepared in Example 1 can achieve efficient sensing of NO2 gas in the concentration range of 10ppb~10ppm within a response time of 120s.
Claims
1. A method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection, characterized in that It is carried out in the following steps:
1. Heat deionized water, anhydrous ethanol and ammonia solution and stir until they are evenly mixed and the temperature is stabilized at 30°C to 70°C to obtain a deionized water-anhydrous ethanol-ammonia solution system; Second, at a temperature of 30°C to 70°C, a SnCl2·2H2O / TEOS anhydrous ethanol solution was added dropwise to a deionized water-anhydrous ethanol-ammonia system, and then hydrolyzed at a temperature of 30°C to 70°C for 0.5h to 3h. Finally, the system was centrifuged, washed, and dried to obtain Sn(OH)4-SiO2 nanospheres.
3. Under nitrogen purge conditions, Sn(OH)4-SiO2 nanospheres and sublimed sulfur powder are placed at the gas outlet and gas inlet of a tube furnace, respectively. Then, under nitrogen purge and high temperature conditions, the Sn(OH)4-SiO2 nanospheres are pyrolyzed and thermally sulfurized to obtain SnO2-SnS2-SiO2 nanospheres. Fourth, the SnO2-SnS2-SiO2 nanospheres and the probe molecule Rhodamine 6G were ultrasonically dispersed in a dichloromethane reagent to obtain a mother solution. A quartz plate treated with piranha solution was vertically inserted into the mother solution, and then the quartz plate was slowly pulled upward to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film.
5. The SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film is dried and aged to obtain a SnO2-SnS2-SiO2-based Rhodamine 6G fluorescent film sensor.
2. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that The volume ratio of deionized water to ammonia water in step 1 is (3-15):8; the volume ratio of anhydrous ethanol to ammonia water in step 1 is (50-100):8; the concentration of ammonia water in step 1 is 25wt.%-28wt.%.
3. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that In step 1, under the conditions of a stirring speed of 100 r / min to 800 r / min and a heating rate of 2°C / min to 10°C / min, deionized water, anhydrous ethanol and ammonia water are heated and stirred until they are uniformly mixed and the temperature is stabilized at 30°C to 70°C.
4. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that The volume ratio of the anhydrous ethanol solution of SnCl2·2H2O / TEOS described in step 2 to the deionized water-anhydrous ethanol-ammonia system is 1:(6~12); the concentration of SnCl2·2H2O in the anhydrous ethanol of SnCl2·2H2O / TEOS described in step 2 is 0.080g / mL~0.016g / mL, and the concentration of TEOS is 0.177g / mL~0.708g / mL; the diameter of the Sn(OH)4-SiO2 nanospheres prepared in step 2 is 175nm~280nm.
5. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that In step 2, the anhydrous ethanol solution of SnCl2·2H2O / TEOS is added dropwise to the deionized water-anhydrous ethanol-ammonia system at a temperature of 30°C to 70°C at a dropping speed of 1mL / min to 5mL / min; the centrifugation in step 2 is specifically performed at a speed of 6000r / min to 10000r / min for 5min to 10min; the washing in step 2 is specifically performed by washing with ultrapure water for 1 to 3 times and then washing with anhydrous ethanol for 2 to 4 times; the drying in step 2 is specifically performed at a temperature of 25°C to 80°C for 4h to 36h.
6. A method for preparing a tin dioxide-tin disulfide-silica-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that the mass ratio of Sn(OH)4-SiO2 nanospheres to sublimated sulfur powder described in step 3 is 1:(0.5~1.5).
7. A method for preparing a tin dioxide-tin disulfide-silica-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that the nitrogen purge condition described in step 3 is 10 mL / min~100 mL / min; the pyrolysis and thermal vulcanization described in step 3 are specifically calcined for 15 min~60 min under the conditions of nitrogen purge condition of 10 mL / min~100 mL / min and temperature of 350°C~500°C.
8. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that The concentration of SnO2-SnS2-SiO2 nanospheres in the mother solution in step 4 is 0.020 g / mL~0.040 g / mL, and the concentration of the probe molecule Rhodamine 6G is 1×10 -2 mol / L~1×10 -7 mol / L; the quartz plate treated with the piranha solution in step 4 is specifically prepared according to the following steps: completely immersing the quartz plate in the piranha solution for 3 minutes to 12 minutes, taking it out and rinsing it with deionized water, repeating the immersion and rinsing 2 to 4 times to obtain the quartz plate treated with the piranha solution; the piranha solution is a mixture of 70wt.% to 98.3wt.% concentrated sulfuric acid solution and 3wt.% to 30wt.% H2O2 solution in a volume ratio of 1:(0.1 to 1).
9. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that In step 4, under the conditions of a temperature of -10°C to 30°C and a power of 100W to 1500W, the SnO2-SnS2-SiO2 nanospheres and the probe molecule Rhodamine 6G are ultrasonically dispersed in a dichloromethane reagent to obtain a mother liquor; in step 4, under the conditions of a pulling temperature of 25°C to 60°C and a pulling air humidity of 40% to 60%, the quartz sheet is slowly pulled upward at a pulling speed of 0.5mm / h to 2mm / h.
10. The method for preparing a tin dioxide-tin disulfide-silicon dioxide-based rhodamine 6G fluorescent thin film sensor for rapid NO2 detection according to claim 1, characterized in that The drying and aging in step 5 is specifically carried out at a temperature of 25° C. to 120° C. for 2 h to 16 h.