Bismuth-Based Gas Sensors: A Comprehensive Review

Abstract

Development of highly sensitive, stable and reliable eco-friendly gas sensors is still an open-ended research domain and thus demands many related materials. Bismuth-based compounds form an important material platform in such developments; however, they are so far not reviewed. This review highlights the detailed gas sensing attributes for a range of gases and humidity for n-type and p-type as well as mixed composite materials and influences of catalytic doping on gas sensing in different bismuth-based composites. The future scope in the development of such gas sensors leading to commercialization is also discussed.

Fluorine-free synthesis of ambient-stable delaminated Ti2CTx (MXene)

“…Mature mechanisms have been proposed to explain surface conductivity changes in the presence of water molecules. 52 At a lower RH, charge transport is secured by proton hopping between the chemisorbed hydroxyl groups. Then, with the increase in the humidity, the physisorbed layers increase, causing H + to move freely.…”

Strategic report on MEMS based carbon monoxide sensor technology for environmental air quality monitoring using unmanned aerial vehicle

“…The sensor device was fabricated using micro fabrication technique , the researchers was used vanadium oxide thin film as a sensing layer using RF sputtering method and the sensors structure was analysed using scanning electron microscopy [120]. The sensors using bismathbased materials was reviewed by the researcher in which both p-type and n-type attributes were discussed and the future scope also discussed by the researchers [121]. The MEMS based gas sensors using SnO 2 nano materials for low concentration gas measurement was discussed.…”

The emergence of MnFe2O4 nanosphere-based humidity sensor: a methodical investigation by scanning Kelvin probe and its deployment in multitudinous applications

“…[11][12][13] In general, humidity sensing is a surface phenomenon whose performance greatly influences various internal and external parameters, such as the structural properties of sensor materials, their surface-tovolume ratio, the microstructure of the sensing layer, surface additives, and temperature. 14 Changes in capacitance, 3,5,9,11 current, 10,12 impedance, 9,13,15 optical intensity, 16 and frequency 17,18 are the explored transduction mechanisms for humidity sensing. Water polarization directly affects the material's conductivity; hence, resistance-based sensing constitutes the major chunk of commercially available humidity sensors and has been acknowledged as a more straightforward, effortless, and primary method among those parameters.…”

“…The type of materials (either n-type or p-type) assigns the positive or negative change in resistance with respect to relative humidity (RH); for p-type materials, the resistance values increase with % RH and vice versa for n-type materials. 12,14,19 To enrich the ever-evolving demands across multiple fields of applications, numerous studies have been devoted to hybrid, organic and inorganic semiconducting material families. Ferrite is one of the members of the inorganic material family containing binary metallic groups with a high density of active sites for the dissociation of water molecules.…”