Abstract
This work reports the recent results achieved at the SENSOR Lab, Brescia (Italy) to address the selectivity of metal oxide based gas sensors. In particular, two main strategies are being developed for this purpose: (i) investigating different sensing mechanisms featuring different response spectra that may be potentially integrated in a single device; (ii) exploiting the electronic nose (EN) approach. The former has been addressed only recently and activities are mainly focused on determining the most suitable configuration and measurements to exploit the novel mechanism. Devices suitable to exploit optical (photoluminescence), magnetic (magneto-optical Kerr effect) and surface ionization in addition to the traditional chemiresistor device are here discussed together with the sensing performance measured so far. The electronic nose is a much more consolidated technology, and results are shown concerning its suitability to respond to industrial and societal needs in the fields of food quality control and detection of microbial activity in human sweat.
Highlights
IntroductionsMetal oxide semiconductors are widely studied and exploited layers in gas-sensing devices, mainly as conductometric sensors (or chemiresistors) i.e., transducing the reaction with the gaseous molecules through a change of the electrical resistance
Consiglio Nazionale delle Ricerche (CNR), Istituto di Bioscienze e Biorisorse (IBBR), Via Madonna del Piano, Academic Editor: Vittorio M
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Summary
Metal oxide semiconductors are widely studied and exploited layers in gas-sensing devices, mainly as conductometric sensors (or chemiresistors) i.e., transducing the reaction with the gaseous molecules through a change of the electrical resistance. Other approaches based on temperature profile protocols or the exploitation of different sensing and transduction mechanisms have been and are still being studied worldwide [3,4]. In this framework, the present paper reviews recent results achieved at the SENSOR Laboratory in Brescia (Italy) to address selectivity. Devices based on electrical (chemiresistor), surface ionization, optical (photoluminescence) and magnetic (magneto-optical Kerr effect) transduction mechanisms are exposed in Section 2 as components of an ambitious goal, still to be reached, aiming to integrate these results into a single, multi-parametric device exploiting different signals from the same material to pursue a selective sensing. Some key-applications are reported to show the effectiveness of this instrument to respond to the need of fields such as food quality control, where the complex composition of the head-space, often composed by hundreds if not thousands of compounds, makes the use of traditional analytical techniques extremely challenging
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