Effect of moisture and molecular weight of polyaniline on H2S sensing characteristics

Gautam, Shivam; Panda, Siddhartha

doi:10.1016/j.snb.2021.130323

Cited by 13 publications

(7 citation statements)

References 62 publications

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“…The absorbance values were low due to the low thickness of the films (in range of 100-433 nm, section S2 in supplementary information) compared to that of the PET substrate (175 µm). A peak at ∼455 nm confirmed polaron to π * transition [42,43], and a free carrier tail was observed in the visible-NIR range [42,43]. The UV-Vis spectra confirmed formation of the PANI-emeraldine salt thin films.…”

Section: Sensing Film Characterizationmentioning

confidence: 76%

Mechanism of NH₃ gas sensing by SnO₂/PANI nanocomposites: charge transport and temperature dependence study

Gautam

Gokhale

Panda

2022

Flex. Print. Electron.

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Metal oxide-Polyaniline (PANI) nanocomposites have shown improved gas sensing characteristics attributed to formation of a p-n junction between the n-type metal oxide and the p-type PANI. The charge transport, grain boundary depletion region, and intragrain resistance are studied to understand the gas sensing mechanism of pristine metal oxide gas sensors. However, gas sensing mechanisms for metal-oxide/PANI nanocomposites have not been studied extensively. In this work, we have studied the gas sensing mechanism of SnO2/PANI nanocomposites using electrochemical impedance spectroscopy (EIS), and temperature dependent gas sensing experiments. Well-defined SnO2 nanoclusters were observed in the PANI matrix. The n-type SnO2 was covered by p-type PANI, and a depletion region was formed at the interface. The presence of the p-n junction depletion region was confirmed by impedance spectroscopy. The polarons in PANI were trapped by NH3 leading to change in the width of the conducting path due to rearrangement of charge carriers along the depletion region. The change in the conduction path along with the trapped polarons enhanced the sensor response. For higher loadings of SnO2, the depletion region was deformed, and the sensor response decreased due to non-uniform boundaries. The nanocomposite showed maximum sensitivity at 35 °C. 1 wt% SnO2 with respect to aniline precursor in in-situ synthesis showed the best response of 37.8% for 100 ppm NH3 at 35 °C. The response was stable for low humidity levels upto 51 %RH. The response increased for higher humidity levels. The sensor response increased from 0.17 to 2.99 upon bending at 7.8 mm diameter due to cracks in the surface. The sensor showed only 10% variation in response after 9 months.

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Section: Sensing Film Characterizationmentioning

confidence: 76%

Mechanism of NH₃ gas sensing by SnO₂/PANI nanocomposites: charge transport and temperature dependence study

Gautam

Gokhale

Panda

2022

Flex. Print. Electron.

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“…XRD pattern of PT0 showed two broad diffraction peaks at 19.7°and 27.66°with low intensity while one comparatively sharper peak at 24.38°. All three peaks indicate the amorphous nature of PANI [32]. However, XRD patterns of PT1, PT2, and PT3 showed strong crystalline peaks owing to the presence of TiO 2 .…”

Section: Materials and Electrical Characterizationmentioning

confidence: 94%

NH₃-detecting room temperature PANI-TiO₂-based flexible gas sensor with EIS-validated sensing mechanism

Jain¹,

Gautam²,

Panda³

2023

Phys. Scr.

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PANI-metal oxide nanocomposites have been studied extensively to improve sensor performance at room temperature. To date, researchers have utilized PANI-TiO2 for sensing NH3, but no elucidation of the sensing mechanism has been reported. In this research work, PANI-TiO2 nanocomposite-based flexible gas sensor for detecting NH3, operating at room temperature, has been investigated. The novelty lies in elucidating the sensing mechanism using electrochemical impedance spectroscopy (EIS) study. Effects of the operating temperature and different humidity levels of the CDA environment on the sensing parameters of the devices are also studied. PANI-TiO2 (10 wt% TiO2 with respect to aniline) device showed the best response of 9.88% against 2 ppm of NH3 at 21 °C. The sensor can detect NH3 as low as 2 ppm within 10 seconds. A low deviation of 3.5% in sensor response after 100 bending cycles was observed. Further, the sensor maintained a near-consistent response even after seven months of fabrication. Moreover, linearity was observed in the I-V analysis, providing further evidence that devices are ohmic. Furthermore, the contributions of the bulk, grain boundary depletion region, and resistance between the electrode and the sensing film in the sensor response were identified by the EIS studies.

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“…Gautham and Panda investigated the effect of moisture and the molecular weight of PANI on H 2 S sensor performance and revealed that their sensor resistance increased in response to increasing H 2 S concentration in a dry environment, but the sensor resistance decreased for the same conditions in a humid environment. [ 182 ] They also reported that the response time and sensitivity are non‐monotonous with respect to the molecular weight of PANI, however they noticed that the response time decreased monotonically with an increasing band‐gap of PANI. Ali and Shano investigated the influence of solvents on PANI nanofibers synthesized using a hydrothermal method and their use in H 2 S sensing.…”

Section: Hydrogen Sulfide Gas Sensorsmentioning

confidence: 99%

Conducting Polymer Based Ammonia and Hydrogen Sulfide Chemical Sensors and Their Suitability for Detecting Food Spoilage

Preethichandra

Gholami

Izake

et al. 2022

Adv Materials Technologies

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health problems such as food poisoning. On the other hand, if non-spoiled food is thrown away as it passes the prespecified expiry date/time, then it is a waste of a valuable food resource. Annual food wastage accounts for one-third of the world's food production and in response to this problem, the Food and Agriculture Organization (FAO) of the United Nations has set one of the sustainable development goals (SDGs) to address it. SDG 12.3 has set the target of halving per capita global food waste at the retail and consumer levels and reducing food loss along both production and supply chains (including post-harvest losses) by 2030. [2] Therefore, a demand for novel food spoilage detection sensors for real-time monitoring of food quality is obvious. Food packaging processes are mainly performed at atmospheric conditions where air-carrying microorganisms may remain inside the sealed food packages. This provides a suitable environment for microorganisms to thrive within the package due to this air capture. Some types of microorganisms, such as Brochothrix thermosphacta, Carnobacterium spp., Lactobacillus spp., Lactococcus spp., Leuconostoc spp., Pediococcus spp., Stretococcus spp., Kurthia zopfii, and Weisella spp, [3] cause disintegration of the food and produce various gasses such as hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), ammonia (NH 3 ), methane (CH 4 ), and other volatile organic compounds (VOCs). [4][5][6][7][8] The CO 2 level in atmospheric air is around 415 ppm and therefore detecting a variation of CO 2 concentration inside a food package at the very early stages of food spoilage is quite challenging. However, there are other types of food packaging called modified atmospheric packaging (MAP), where the package is vacuum-sealed or filled with different gases such as nitrogen combined with an antimicrobial active gas, such as carbon dioxide, to provide a barrier against food spoilage and improve the shelf-lifetime of the product. [9] There are multiple methods which are proposed by various research groups either for detecting the food spoilage or monitoring the food quality at early stages. Various parameters such as O 2 /CO 2 /NH 3 /H 2 S/VOC concentrations, temperature, humidity, pH value, and any specific chemicals inside the food package can be detected using a wide range of measurement techniques. [9] Figure 1 illustrates the three most common food categories and the gases that are emitted by microorganisms Food security is critical for the sustainability of society. The spoilage of stocked food is an ongoing problem that causes significant losses to the global economy. Novel portable analytical platforms that provide timely information on the condition of food stock can support informed decisionmaking on the safety of food consumption as well as on maximization of food storage lifetime. Ammonia (NH 3 ) and hydrogen sulfide (H 2 S) are two of the major harmful gases that are produced due to bacteria activity during the food spoilage process. The timely detection of these gases in food stocks h...

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Effect of moisture and molecular weight of polyaniline on H2S sensing characteristics

Cited by 13 publications

References 62 publications

Mechanism of NH₃ gas sensing by SnO₂/PANI nanocomposites: charge transport and temperature dependence study

Mechanism of NH₃ gas sensing by SnO₂/PANI nanocomposites: charge transport and temperature dependence study

NH₃-detecting room temperature PANI-TiO₂-based flexible gas sensor with EIS-validated sensing mechanism

Conducting Polymer Based Ammonia and Hydrogen Sulfide Chemical Sensors and Their Suitability for Detecting Food Spoilage

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Effect of moisture and molecular weight of polyaniline on H2S sensing characteristics

Cited by 13 publications

References 62 publications

Mechanism of NH3 gas sensing by SnO2/PANI nanocomposites: charge transport and temperature dependence study

Mechanism of NH3 gas sensing by SnO2/PANI nanocomposites: charge transport and temperature dependence study

NH3-detecting room temperature PANI-TiO2-based flexible gas sensor with EIS-validated sensing mechanism

Conducting Polymer Based Ammonia and Hydrogen Sulfide Chemical Sensors and Their Suitability for Detecting Food Spoilage

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Mechanism of NH₃ gas sensing by SnO₂/PANI nanocomposites: charge transport and temperature dependence study

Mechanism of NH₃ gas sensing by SnO₂/PANI nanocomposites: charge transport and temperature dependence study

NH₃-detecting room temperature PANI-TiO₂-based flexible gas sensor with EIS-validated sensing mechanism