Aqueous and alcoholic syntheses of tungsten trioxide powders for NO2 detection

Guidi, V.; Blo, M.; Butturi, Maria Angela; Carotta, M.C.; Galliera, S.; Giberti, A; Malagù, C.; Martinelli, G.; Piga, Matteo; Sacerdoti, M.; Vendemiati, B.

doi:10.1016/j.snb.2003.12.055

Cited by 30 publications

(12 citation statements)

References 20 publications

(21 reference statements)

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“…The temperature dependences of lattice constant and magnetic susceptibility of ε-WO 3 x -were studied at low temperatures [2]. Recently, WO 3 was found to have applications, for example, to electrochromic and electrochemically functional materials [3] and gas sensors (NO, NO 2 ) [4,5]. As observed in the rare-earth aluminates [6,7], the phase-transition temperatures increase monotonically with the decrease in size of the A ion in ABX 3 perovskite crystals.…”

Section: Introductionmentioning

confidence: 99%

Dielectric anomaly of tungsten trioxide WO₃ with giant dielectric constant

Hirose

Furukawa

2006

Physica Status Solidi (a)

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Temperature dependences of the dielectric constant and the dielectric dispersion of a WO 3 single crystal have been measured in the temperature range from -180 °C to 100 °C and at frequencies from 20 Hz to 1 MHz. A large dielectric anomaly has been observed at 16.2 °C on heating, and the peak value of the dielectric constant is as large as about 10 5 . The anomaly has large thermal hysteresis, long relaxation time and large dielectric dispersion. A transition from ferrielectric state to ferroelectric state induced by an electric field has been observed by D -E hysteresis measurement below room temperature. In the triclinic phase, the coexistence of the monoclinic(II) and the monoclinic(I) phases was observed by EPR (ESR) measurements of doped Cr 3+ ions. These results suggest that a frustration of the antiferroelectric and ferroelectric states exists at the dielectric anomaly temperature. The dielectric anomaly can be interpreted as a result of the phase transition between the triclinic phase with micro ferroelectric regions and the antiferroelectric monoclinic(I) phase.

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Section: Introductionmentioning

confidence: 99%

Dielectric anomaly of tungsten trioxide WO₃ with giant dielectric constant

Hirose

Furukawa

2006

Physica Status Solidi (a)

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“…The broadening was very rapid during the first milling time, but was quite marginal after that. The size variation of milled NPs was quantitatively calculated using the Scherrer formula [13,17] and also observed by TEM [18]. Both methods showed consistent results, as presented in Fig.…”

Section: Resultsmentioning

confidence: 62%

Synthesis, Separation and Electrical Properties of WO_3-xNanopowders via Partial Pressure High Energy Ball-Milling

Mohammad

2009

Acta Phys. Pol. A

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Reduction processes of WO 3 nanopowder either with carbon or with hydrogen were observed using X-ray powder diffraction and transmission electron microscope. The phase transformations, separation, grain size and electrical conductivity of WO 3−x nanopowder during reductions via partial pressure high energy ball-milling have been studied. During the carbon-reduction process the monoclinic WO3 structure transforms to nonstoichiometric Magneli phases W40O118, WO2.9 and finally to WO2 and W mixed phases. The Magneli WO3−x phases exhibit specific fringe contrast imaging of well-ordered crystallographic shear planes. In comparison, the monoclinic WO3 structure transforms to hydrate WO3·1/3H2O, hexagonal WO3, non-stoichiometric WO2.7 and finally to WO2 and W mixed phases during the hydrogen-reduction process. The inclusion of hydrogen atoms between the WO6 octahedral structure shifts the reduction steps to lower milling times. It demonstrates that the formation of hydrate WO3 phases enhances the amenability of the system to reduction. The activation energy for conduction was deduced from the Arrhenius equation and was found to depend on oxygen partial pressure or presence of the hydrogen atoms. The defect band model was used for interpretation of these behaviors. It supposes that the surface oxygen vacancies introduce donor levels in the gap of semiconductor, so free electrons are produced by reduction.

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“…The variety of sensors chosen lays upon the will to verify if chemoresistive sensors can detect variations as a whole technology, or if only some particular semiconductors can be used for screening/detection purposes, and to visualize possible correlations between their response behaviors. Further details in the sensors' functioning, the differences between the various semiconductor materials, and their characterizations can be found in literature [1][2][3][4][5][6][7][33][34][35][36][37][38][39][40][41][42][43][44][45]. The responses are standardly defined as the average value between three output voltages measured by the sensor from the same sample, as shown in the following formula [6]:…”

Section: Sensors Technologymentioning

confidence: 99%

Nanostructured Chemoresistive Sensors for Oncological Screening and Tumor Markers Tracking: Single Sensor Approach Applications on Human Blood and Cell Samples

Landini

Anania

Astolfi

et al. 2020

Sensors

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Preventive screening does not only allow to preemptively intervene on pathologies before they can harm the host; but also to reduce the costs of the intervention itself; boosting the efficiency of the NHS (National Health System) by saving resources for other purposes. To improve technology advancements in this field; user-friendly yet low-cost devices are required; and various applications for gas sensors have been tested and proved reliable in past studies. In this work; cell cultures and blood samples have been studied; using nanostructured chemoresistive sensors; to both verify if this technology can reliably detect tumor markers; and if correlations between responses from tumor line metabolites and the screening outcomes on human specimens could be observed. The results showed how sensors responded differently to the emanations from healthy and mutant (for cells) or tumor affected (for blood) samples, and how those results were consistent between them, since the tumoral specimens had higher responses compared to the ones of their healthy counterparts. Even though the patterns in the responses require a bigger population to be defined properly; it appeared that the different macro-groups between the same kind of samples are distinguishable from some of the sensors chosen in the study; giving promising outcomes for further research.

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Aqueous and alcoholic syntheses of tungsten trioxide powders for NO2 detection

Cited by 30 publications

References 20 publications

Dielectric anomaly of tungsten trioxide WO₃ with giant dielectric constant

Dielectric anomaly of tungsten trioxide WO₃ with giant dielectric constant

Synthesis, Separation and Electrical Properties of WO_3-xNanopowders via Partial Pressure High Energy Ball-Milling

Nanostructured Chemoresistive Sensors for Oncological Screening and Tumor Markers Tracking: Single Sensor Approach Applications on Human Blood and Cell Samples

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Aqueous and alcoholic syntheses of tungsten trioxide powders for NO2 detection

Cited by 30 publications

References 20 publications

Dielectric anomaly of tungsten trioxide WO3 with giant dielectric constant

Dielectric anomaly of tungsten trioxide WO3 with giant dielectric constant

Synthesis, Separation and Electrical Properties of WO3-xNanopowders via Partial Pressure High Energy Ball-Milling

Nanostructured Chemoresistive Sensors for Oncological Screening and Tumor Markers Tracking: Single Sensor Approach Applications on Human Blood and Cell Samples

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Product

Resources

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Dielectric anomaly of tungsten trioxide WO₃ with giant dielectric constant

Dielectric anomaly of tungsten trioxide WO₃ with giant dielectric constant

Synthesis, Separation and Electrical Properties of WO_3-xNanopowders via Partial Pressure High Energy Ball-Milling