Extraordinary performance of semiconducting metal oxide gas sensors using dielectric excitation

Potyrailo, Radislav A.; Go, Steven; Sexton, Daniel; Li, Xiaxi; Alkadi, Nasr; Kolmakov, Andrei; Amm, Bruce; St-Pierre, Richard; Scherer, Brian; Nayeri, M.; Wu, Guang; Collazo-Davila, Christopher; Forman, Doug; Calvert, C. C.; Mack, Craig; McConnell, Philip

doi:10.1038/s41928-020-0402-3

Cited by 125 publications

(101 citation statements)

References 47 publications

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“…Compared to the conventional MOS and conducting polymer-based sensors that usually are used in gas-sensing arrays, the ability of the suberin-based sensors to respond and distinguish high concentrations of VOCs is noteworthy as these conventional gas sensors operate in dynamic ranges only up to ppm concentrations of VOC, losing resolution for higher concentrations, like those tested here, in the range of % vol [ 30 , 31 ].…”

Section: Resultsmentioning

confidence: 99%

Sustainable plant polyesters as substrates for optical gas sensors

Rodrigues

Palma

Correia

et al. 2020

Materials Today Bio

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The fast and non-invasive detection of odors and volatile organic compounds (VOCs) by gas sensors and electronic noses is a growing field of interest, mostly due to a large scope of potential applications. Additional drivers for the expansion of the field include the development of alternative and sustainable sensing materials. The discovery that isolated cross-linked polymeric structures of suberin spontaneously self-assemble as a film inspired us to develop new sensing composite materials consisting of suberin and a liquid crystal (LC). Due to their stimuli-responsive and optically active nature, liquid crystals are interesting probes in gas sensing. Herein, we report the isolation and the chemical characterization of two suberin types (from cork and from potato peels) resorting to analyses of gas chromatography–mass spectrometry (GC-MS), solution nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS). The collected data highlighted their compositional and structural differences. Cork suberin showed a higher proportion of longer aliphatic constituents and is more esterified than potato suberin. Accordingly, when casted it formed films with larger surface irregularities and a higher C/O ratio. When either type of suberin was combined with the liquid crystal 5CB, the ensuing hybrid materials showed distinctive morphological and sensing properties towards a set of 12 VOCs (comprising heptane, hexane, chloroform, toluene, dichlormethane, diethylether, ethyl acetate, acetonitrile, acetone, ethanol, methanol, and acetic acid). The optical responses generated by the materials are reversible and reproducible, showing stability for 3 weeks. The individual VOC-sensing responses of the two hybrid materials are discussed taking as basis the chemistry of each suberin type. A support vector machines (SVM) algorithm based on the features of the optical responses was implemented to assess the VOC identification ability of the materials, revealing that the two distinct suberin-based sensors complement each other, since they selectively identify distinct VOCs or VOC groups. It is expected that such new environmentally-friendly gas sensing materials derived from natural diversity can be combined in arrays to enlarge selectivity and sensing capacity.

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Section: Resultsmentioning

confidence: 99%

Sustainable plant polyesters as substrates for optical gas sensors

Rodrigues

Palma

Correia

et al. 2020

Materials Today Bio

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“…Metal and mixed metal and semiconductor oxides are widely applied in several fields, as supercapacitors [1][2][3], gas sensors based on chemoresistivity [4][5][6][7][8] or dielectric excitation [9,10], heterojunctions [11,12], energy storage in batteries [13][14][15], and electrochemistry [16][17][18]. Their properties can be varied in different ways, by doping [19,20], capping, and controlling the structure, shape, and size with bottom-up and top-down approaches [21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Room Temperature Syntheses of ZnO and Their Structures

et al. 2021

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ZnO has many technological applications which largely depend on its properties, which can be tuned by controlled synthesis. Ideally, the most convenient ZnO synthesis is carried out at room temperature in an aqueous solvent. However, the correct temperature values are often loosely defined. In the current paper, we performed the synthesis of ZnO in an aqueous solvent by varying the reaction and drying temperatures by 10 °C steps, and we monitored the synthesis products primarily by XRD). We found out that a simple direct synthesis of ZnO, without additional surfactant, pumping, or freezing, required both a reaction (TP) and a drying (TD) temperature of 40 °C. Higher temperatures also afforded ZnO, but lowering any of the TP or TD below the threshold value resulted either in the achievement of Zn(OH)2 or a mixture of Zn(OH)2/ZnO. A more detailed Rietveld analysis of the ZnO samples revealed a density variation of about 4% (5.44 to 5.68 gcm−3) with the synthesis temperature, and an increase of the nanoparticles’ average size, which was also verified by SEM images. The average size of the ZnO synthesized at TP = TD = 40 °C was 42 nm, as estimated by XRD, and 53 ± 10 nm, as estimated by SEM. For higher synthesis temperatures, they vary between 76 nm and 71 nm (XRD estimate) or 65 ± 12 nm and 69 ± 11 nm (SEM estimate) for TP =50 °C, TD = 40 °C, or TP = TD = 60 °C, respectively. At TP = TD = 30 °C, micrometric structures aggregated in foils are obtained, which segregate nanoparticles of ZnO if TD is raised to 40 °C. The optical properties of ZnO obtained by UV-Vis reflectance spectroscopy indicate a red shift of the band gap by ~0.1 eV.

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“…An explanation for this phenomenon is that both the PID and the ETH signals degrade equally with the distance; hence, the primary variables dictating the correlation are the distance between the PID and the alcohol sensor, and how thin the odor filaments are within the turbulent regime. Furthermore, using an improved dielectric excitation method and the resulting impedance measurements from the improved designs,Potyrailo et al (2020) have shown linear responses to a varying range of concentrations from metal oxide sensors.…”

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confidence: 99%