Monomer: Design of ZnO Nanostructures (Nanobush and Nanowire) and Their Room-Temperature Ethanol Vapor Sensing Signatures

Abstract

Ethanol serves as a biomarker as well as a chemical reagent for several applications and has been predominantly used as an alternative fuel (E10 and E85). Development of sensors for the detection and monitoring of ethanol vapor at lower operating temperatures has gathered momentum in the recent past. In this work, we reported the synthesis of self-assembled ZnO nanowires using electrospun technique without using any external surfactants or capping agents and their room temperature ethanol sensing properties. An inherent template namely monomer of the polymer poly(vinyl alcohol) (PVA) with two different molecular weights (14 000 and 140 000 g mol) was used along with the precursor zinc acetate dihydrate. The ZnO-PVA nanofibers have been tranformed to ZnO nanospheres and nanowires after calcination. The ratio of zinc precursor concentration to PVA polymer led to the enhanced carrier concentration of the resultant ZnO nanowire that enhanced, in turn, the sensing response toward ethanol vapor. The developed sensing elements have been systematically characterized to correlate their structural, morphological, and electrical properties with the respective room-temperature ethanol-sensing characteristics. The role of grain features and low activation energy of ZnO nanowires in coordination with the low dipole moment of ethanol resulted in the excellent response of 78 toward 100 ppm at room temperature with ultra-sensitive response and recovery times (9 and 12 s, respectively).

Development of an acetone sensor using nanostructured Co3O4 thin films for exhaled breath analysis

“…The activation energy of the deposited sensing elements was calculated using the Arrhenius equation (eqn (11)), 42,43…”

“…As far as the properties of gas sensing elements are concerned, the morphology, defect state, crystallinity, and surface roughness decide the selective detection of target analytes. 21,42 Enhanced crystallinity with crystal reorientation, shi in the defect states, elongated growth of aggregated nanograins with improved roughness prole of the lm deposited at 773 K, could have enhanced the surface with more reactive oxygen sites in-turn resulted in the increased sensing response. On the Fig.…”

Synthesis, Characterization, and Three-Dimensional Structure Generation of Zinc Oxide-Based Nanomedicine for Biomedical Applications

“…In gas sensors, the pore properties are important factors because they allow adsorbates into internal surfaces to ensure adequate adsorption performance. For example, highly sensitive and selective gas sensors of ZnO nanowires/NPs were able to detect ethanol and acetone quickly and accurately [187,188]. Nano-brush and pearl chain-like ZnO nanowires were developed for the selective and sensitive detection of ethanol [187].…”

“…For example, highly sensitive and selective gas sensors of ZnO nanowires/NPs were able to detect ethanol and acetone quickly and accurately [187,188]. Nano-brush and pearl chain-like ZnO nanowires were developed for the selective and sensitive detection of ethanol [187]. Zhou et al [188] reported an interlocking p + n field-effect transistor circuit of Mn-doped ZnO NPs for detecting acetone as low as 2 ppm, even under conditions of high relative humidity (>85%).…”

Sensitive Cross-Linked SnO2:NiO Networks for MEMS Compatible Ethanol Gas Sensors

“…The resistive ethanol sensors used semiconducting metal oxides (MOS) as sensing materials are popular due to their advantages, such as cheap, nontoxic, stable, simple processing, and higher sensitivity performance [6][7][8]. Typically, various nanostructured MOS including nanowires, nanoplates, hollow spheres, and heterostructures can greatly enhance the diffusion of analyte gases and facilitate the charge transport, leading to high sensitivity and fast sensing-recovery process [9][10][11][12][13][14][15][16][17][18]. However, most of the reported sensors are fabricated by drop-coating or screen printing the nanostructured MOS solution onto ceramic tubes or plates, which results in large sensor-to-sensor variations, large size, and high power consumption of 200-1000 mW [7,[19][20][21][22][23].…”