Influence of major parameters on the sensing mechanism of semiconductor metal oxide based chemiresistive gas sensors: A review focused on personalized healthcare

Spray-Deposited Rare Earth Metal Ion (Sm3+, Ce3+, Pr3+, La3+)-Doped CdO Thin Films for Enhanced Formaldehyde Gas Sensing Characteristics

“…As the electron concentration rises, the trapped electrons rapidly return to the CdO conduction band, providing the surface depletion layer, lower potential barrier, and reduced resistance. 27 , 38 The sensor has good formaldehyde gas sensing capability for two reasons ( Figure 8 ). RE-doped CdO thin films are generated from many small particles or crystals.…”

Chemiresistive NH3 detection at sub-zero temperatures by polypyrrole- loaded Sn1−xSbxO2 nanocubes

“…31 While some framework morphologies shall perform the work of unfurling the polymer network more efficiently, the overall transport properties of the composite material are expected to play a crucial role in deciphering the mechanism of electron conduction and the surface adsorption-desorption dynamics at low temperatures, 32 therefore making the material suitable for low temperature gas sensing. SnO 2 (with 110 plane as the most active surface) is a popular wide band-gap semiconducting sensor material, 7,8,11 while antimony in the 3+ state has an ionic radius similar to that of Sn 4+ with the additional benefit that Sb 3+ has excess 5s 2 electrons to make the doped SnO 2 electron-rich, thus projecting Sb-doped SnO 2 as a potential candidate for the above-mentioned framework. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) are standard tools to delineate surface morphology and microstructural details of materials.…”

“…[1][2][3][4][5] This popularity of chemiresistive sensors has not only made the consumer society cautious of factors like air quality factors, and work place exposure limits to gases like SO x and NO x but has also paved the way to a tremendous amount of research and investment that can optimize sensor performance and their utility by multifold. 7,8 Chemiresistive gas sensors are quite flexible in terms of operational temperature conditions. [9][10][11] Be it detecting trace pollutants in industrial chimneys where gases are emanated at several hundred degrees of temperature or be it detecting pollutants in vehicular exhausts or those at room temperature, chemiresistive sensors have been successfully applied with full functioning under a variety of temperature conditions at and above room temperature.…”

“…1–5 This popularity of chemiresistive sensors has not only made the consumer society cautious of factors like air quality factors, and work place exposure limits to gases like SO x and NO x but has also paved the way to a tremendous amount of research and investment that can optimize sensor performance and their utility by multifold. 7,8…”

Ammonia breath analysis

“…This is a highly versatile group of materials and there are many parameters that can influence their sensing properties, including porosity, doping, crystal phase, operating temperature, humidity, and particle size and morphology. 34 For example, it was shown that by operating a Si-doped α-MoO 3 sensor for NH 3 breath analysis at 400 °C it can be operated at 90% RH, as is required for breath analysis (Fig. 3).…”