Nitrogen dioxide sensor based on conjugated organic framework / perovskite composite
A nitrogen dioxide sensor was prepared by combining the conjugated organic framework TpPa-1 with perovskite Cs2PdBr6, which solved the problems of complex preparation and insufficient detection sensitivity of existing sensors, and realized low-cost and high-sensitivity nitrogen dioxide detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU UNIV
- Filing Date
- 2022-03-29
- Publication Date
- 2026-05-12
AI Technical Summary
Existing nitrogen dioxide sensors are inadequate in terms of manufacturing cost, ease of use, and detection sensitivity, making it difficult to meet market demands.
A nitrogen dioxide sensor was fabricated using a conjugated organic framework TpPa-1 and a perovskite Cs2PdBr6 composite. A film material was formed by drop-coating and heating on interdigitated electrodes, and combined with a silver-palladium alloy as a substrate to detect nitrogen dioxide changes.
It achieves convenient device fabrication, low detection limit, good gas selectivity, and can detect nitrogen dioxide as low as 40 ppb, with stable device performance.
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Figure CN114894853B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor materials technology, specifically relating to a nitrogen dioxide sensor based on a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite, its preparation method, and its application in environmental nitrogen dioxide detection. Background Technology
[0002] Modern society is highly dependent on energy generated from the combustion of fossil fuels. Data shows that emissions from automobile internal combustion engines cause serious environmental and health problems. Nitrogen dioxide, as a representative nitrogen oxide, is recognized as one of the most dangerous air pollutants and is also an important biomarker for lung tissue and irritable bowel disease. Its high-sensitivity detection is of great significance in environmental protection and human health monitoring. Therefore, real-time monitoring of nitrogen dioxide has attracted much attention from researchers. To meet current market demands for sensors that are inexpensive, practical, and easy to manufacture, there is an urgent need to develop a novel nitrogen dioxide sensor. Summary of the Invention
[0003] To address the above issues, this invention employs a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite to fabricate a nitrogen dioxide sensor, and detects different concentrations of nitrogen dioxide by observing the sensor's current changes at different nitrogen dioxide concentrations. This invention tested the current changes of the nitrogen dioxide sensor under different nitrogen dioxide concentrations and the device's recoverability. First, the device was placed in a pure nitrogen environment to measure its current; then, the nitrogen dioxide content in the environment was continuously increased, and the current was measured again.
[0004] Specifically, the present invention adopts the following technical solution:
[0005] A nitrogen dioxide sensor based on a conjugated organic framework / perovskite composite includes a membrane material and interdigitated electrodes; the membrane material is a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite.
[0006] The method for preparing the nitrogen dioxide sensor based on the conjugated organic framework / perovskite composite includes the following steps: a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite solution is drop-coated onto an interdigitated electrode, followed by heating to obtain the nitrogen dioxide sensor based on the conjugated organic framework / perovskite composite. The heating and drying temperature of the device is 40–90°C for 4–6 min, preferably 60°C for 5 min.
[0007] The nitrogen dioxide sensor of the present invention includes a membrane material and interdigitated electrodes; the thickness of the membrane material is 10-100 μm; the interdigitated electrodes are existing products, with aluminum oxide (Al2O3) as the substrate, and a silver-palladium alloy (Ag-Pd) disposed on the substrate; the interdigitated electrode has an interdigitated width of 200-300 μm and an interdigitated spacing of 100-200 μm; the thickness of the substrate is 1-2 mm; and the thickness of the silver-palladium alloy is 100-200 nm.
[0008] This invention discloses the application of the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite in the preparation of nitrogen dioxide sensors; or the application of the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite in the preparation of nitrogen dioxide sensor membrane materials.
[0009] In this invention, a conjugated organic framework TpPa-1, a solvent, and perovskite Cs2PdBr6 are mixed to obtain a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite solution. The solvent is a conventional organic solvent. The mixing is performed by ultrasonic dispersion or stirring. The weight ratio of conjugated organic framework TpPa-1 to perovskite Cs2PdBr6 is 6 to 40:32. As an example: A TpPa-1 conjugated organic framework is ultrasonically dispersed with an alcohol solvent to obtain a TpPa-1 dispersion. Preferably, the ultrasonic dispersion time is 0.5–2 h, and the ratio of TpPa-1 to tert-butanol is 20–40 mg:10 mL, preferably 30 mg:10 mL. Perovskite Cs2PdBr6, a solvent, and the TpPa-1 dispersion are stirred and mixed to obtain a TpPa-1 / perovskite Cs2PdBr6 composite solution. Preferably, the stirring speed is 800–3000 rpm. The ratio of perovskite Cs2PdBr6 to the dispersing solvent is 150–180 mg:1 mL, preferably 160 mg:1 mL. The dispersing solvent is a mixture of N,N-dimethylformamide and dimethyl sulfoxide, preferably a 1:1 volume ratio of N,N-dimethylformamide and dimethyl sulfoxide. Preferably, the perovskite Cs2PdBr6 is dissolved in the dispersion solvent by heating and then mixed with the conjugated organic framework TpPa-1 dispersion. The heating temperature is 40-70°C and the time is 1-3 min, preferably 50°C and 2 min.
[0010] The above-mentioned nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex is applied to the detection of nitrogen dioxide.
[0011] The preparation method of the nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex is as follows:
[0012] (1) Clean the finger electrodes and dry them;
[0013] (2) Mix TpPa-1 with tert-butanol to obtain solution one;
[0014] (3) Dissolve perovskite Cs2PdBr6 in a dispersion solvent and heat at 40-60℃ to obtain solution two;
[0015] (4) Add solution 2 to solution 1, stir, and then let stand to obtain solution 3;
[0016] (5) The lower layer precipitate solution (conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex solution) was drop-coated onto the surface of the interdigitated electrode and dried by heating to obtain a nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex.
[0017] Compared with the prior art, the present invention utilizing the above technical solution has the following advantages:
[0018] (1) The device is easy to fabricate and simple to operate;
[0019] (2) The detection limit is low; the lowest detection concentration for nitrogen dioxide is lower than that for common metal oxides.
[0020] (3) The device has excellent gas selectivity.
[0021] (4) The device performance is stable. Attached Figure Description
[0022] Figure 1 The image shows the SEM spectrum of perovskite Cs2PdBr6.
[0023] Figure 2 The image shows the SEM spectrum of the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex.
[0024] Figure 3 The XRD pattern of the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex.
[0025] Figure 4 This is a schematic diagram of the structure of a nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex.
[0026] Figure 5 The graph shows the response of the nitrogen dioxide sensor, which is a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex, as a function of nitrogen dioxide concentration.
[0027] Figure 6The response / recovery time plot of the nitrogen dioxide sensor for the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex.
[0028] Figure 7 The graph shows the selectivity of the sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex as a function of the amount of conjugated organic framework TpPa-1.
[0029] Figure 8 The response diagram is shown for the perovskite Cs2PdBr6 sensor.
[0030] Figure 9 The response diagram is for the TpPa-1 conjugated organic framework sensor. Detailed Implementation
[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise stated, the reagents, materials, instruments, etc. used in the following embodiments can be obtained by commercial means; unless otherwise specified, the parameters and environment of the embodiments are conventional techniques; the substrate and interdigitated electrodes are existing products, and the specific preparation operations and experimental methods are conventional techniques.
[0032] Synthesis of perovskite Cs2PdBr6
[0033] (1) Synthesis of perovskite Cs2PdBr6:
[0034] Weigh cesium bromide (4.2562 g, 20 mmol) and palladium bromide (2.6623 g, 10 mmol) and place them in a hydrogen bromide solution (10 mL). Heat and stir at 85 °C for 10 min. Then add 1 mL of dimethyl sulfoxide at 120 °C and stir for 10 min. Turn off the heating plate, cool to room temperature, filter the product, wash with water and toluene, and dry in a vacuum oven at 100 °C for 10 h to obtain the perovskite Cs₂PdBr₆, which has a non-hollow structure. Its SEM microstructure is shown below. Figure 1 As shown, its X-ray diffraction pattern is as follows: Figure 3 As shown in the figure, Cs2PdBr6 has an octahedral structure. The synthesized Cs2PdBr6 corresponds exactly to the standard Cs2PdBr6 PDF card, confirming successful synthesis.
[0035] Example 1: Fabrication of a sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite:
[0036] (a) The interdigitated electrodes were ultrasonically cleaned with deionized water and ethanol for 10 min respectively and then dried. The interdigitated length was 7 mm, the width was 0.2 mm, the interdigitated spacing was 0.2 mm, the substrate thickness was 1.5 mm, and the silver-palladium alloy thickness was 150 nm.
[0037] (b) Take 30 mg of TpPa-1 (CAS NO.: 1414350-37-0) and mix it with 10 mL of tert-butanol and sonicate for 1 h to obtain solution one;
[0038] (c) Dissolve the above perovskite Cs2PdBr6 (160 mg) in 1 mL of a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 1:1, and heat at 50 °C for 2 min to obtain solution two;
[0039] (d) Take 200 μL of solution two and add it to 10 mL of solution one, and stir at 1500 rpm for 30 min to obtain a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex solution. Its SEM microstructure is shown below. Figure 2 As shown, its X-ray diffraction pattern is as follows: Figure 3 As shown.
[0040] Depend on Figure 2 It can be seen that the conjugated organic framework TpPa-1 is dispersed on the surface of perovskite Cs2PdBr6, presenting a flower-like structure; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 3 It can be seen that the peaks of the conjugated organic framework TpPa-1 and Cs2PdBr6 still exist, and no phase transition occurs when they recombine.
[0041] (e) Let the above solution stand for 12 h to obtain solution three;
[0042] (f) The lower-layer precipitate solution was dropped onto the surface of the interdigitated electrode and heated with an infrared drying lamp to obtain a nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex. The amount of conjugated organic framework TpPa-1 added reached 48.4 wt%. The schematic diagram of the sensor structure is shown below. Figure 4 As shown, the thickness of the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite film is 30 μm.
[0043] Comparative Example
[0044] Based on Example 1, the perovskite Cs2PdBr6 was omitted, resulting in a TpPa-1 conjugated organic framework device; based on Example 1, the TpPa-1 conjugated organic framework was omitted, resulting in a Cs2PdBr6 perovskite device.
[0045] This invention employs a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite to fabricate a nitrogen dioxide sensor, and detects different concentrations of nitrogen dioxide by observing the current changes of the sensor under different nitrogen dioxide concentrations. This invention tests the current changes of the nitrogen dioxide sensor under different nitrogen dioxide concentrations and the device's recoverability. First, the device is placed in a pure nitrogen environment to measure its current; then, the nitrogen dioxide content in the environment is continuously increased, and the current is measured again.
[0046] Example 2: Response Measurement Experiment of Conjugated Organic Framework TpPa-1 / Perovskite Cs2PdBr6 Complex Sensor under Different Nitrogen Dioxide Concentrations
[0047] The nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite prepared in Example 1 was placed in a testing machine. Under a constant voltage of 5 V, the response change of the device in the range of 40 ppb-10 ppm was tested, and the results are as follows. Figure 5 As shown, the sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 complex exhibits a significant response to different concentrations of nitrogen dioxide atmosphere (diluted with nitrogen gas); the detection limit can reach 40 ppb. In a 10 ppm NO2 environment, the sensor's response and recovery times are 71 s and 254 s, respectively, as shown in the figures. Figure 6 As shown.
[0048] Example 3: Sensor Response Measurement Experiment under Different Gas Environments
[0049] The amount of conjugated organic framework TpPa-1 added is calculated by dividing the amount of TpPa-1 by the weight of the TpPa-1 / perovskite Cs2PdBr6 composite. Based on Example 1, by changing the amount of solution 2 added in step (d), nitrogen dioxide sensors based on the TpPa-1 / perovskite Cs2PdBr6 composite with different amounts of TpPa-1 can be obtained.
[0050] Using conjugated organic framework TpPa-1 devices, perovskite Cs2PdBr6 devices, and a sensor based on a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite as test objects, the prepared sensors were placed in a testing machine. Under a constant voltage of 5 V, the responses of the devices were tested in atmospheres of 2 ppm CO, HCl, NH3, NO, NO2, SO2, and H2 (diluted with nitrogen). The responses with different amounts of conjugated organic framework TpPa-1 were also tested. The results are as follows: Figure 7As shown, the sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite exhibits the most significant response to nitrogen dioxide; the selectivity improvement is most pronounced when the amount of conjugated organic framework TpPa-1 reaches 30 mg (48.4 wt%). A magnified response diagram of the perovskite Cs2PdBr6 device is shown below. Figure 8 The response of the conjugated organic framework TpPa-1 device is shown in [reference needed]. Figure 9 It is clear that the perovskite Cs2PdBr6 device and the conjugated organic framework TpPa-1 device have extremely low nitrogen dioxide responsiveness and cannot be used as sensors.
[0051] In summary, this invention utilizes a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite to fabricate a simple resistive thin-film sensor, enabling the detection of nitrogen dioxide at different concentrations with a detection limit as low as 40 ppb and excellent gas selectivity. This invention realizes the application of perovskite in the field of nitrogen dioxide sensing. The nitrogen dioxide sensor based on the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite of this invention has high application value for the future detection of environmental nitrogen dioxide.
Claims
1. A method for detecting nitrogen dioxide using a nitrogen dioxide sensor based on a conjugated organic framework / perovskite complex, characterized in that, A nitrogen dioxide sensor based on a conjugated organic framework / perovskite composite is placed into the detection system, and nitrogen dioxide detection is completed by applying an electric current. The nitrogen dioxide sensor based on the conjugated organic framework / perovskite composite includes a membrane material and interdigitated electrodes. The membrane material is a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite. The thickness of the membrane material is 10-100 μm. μm; The preparation method of the nitrogen dioxide sensor based on the conjugated organic framework / perovskite composite includes the following steps: mixing perovskite Cs2PdBr6, conjugated organic framework TpPa-1, and solvent to obtain a conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite solution; drop-coating the conjugated organic framework TpPa-1 / perovskite Cs2PdBr6 composite solution onto interdigitated electrodes, and then heating to obtain a nitrogen dioxide sensor based on the conjugated organic framework / perovskite composite; heating and drying the device at a temperature of 40-90℃ for 4-6 min; the weight ratio of conjugated organic framework TpPa-1 to perovskite Cs2PdBr6 is 6-40:
32.
2. The method for detecting nitrogen dioxide according to claim 1, characterized in that: The detection of nitrogen dioxide is performed based on the current.