UV-Light-Induced Fluctuation Enhanced Sensing by WO₃-Based Gas Sensors

Abstract

WO 3 -based gas sensors were investigated under UV-light irradiation and at different working temperatures with the object of achieving superior sensitivity and selectivity. Resistance fluctuations in the WO 3 layer were studied together with dc resistance measurements. The data were taken in synthetic air, ethanol, nitrogen dioxide, and mixtures of these gases. We conclude that UV irradiation can easily be applied to enhance the gas sensing properties of a WO 3 layer.

Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

“…UV light has often been used exclusively for promoting desorption of surface species from the sensing layer, rather than to modify its sensing properties. It is only very recently that UV activation in addition to heating has been explored for improving sensitivity and selectivity of metal oxides [17]. …”

Fluctuation-Enhanced Sensing: Review of Practical Issues

“…Selected wavelengths of the UV light can modulate the physical properties of the gas sensing layer (e.g., DC resistance, lowfrequency resistance fluctuations) [55]. We observed that changes of DC resistance induced by UV irradiation are independent of the changes of the recorded low-frequency noise [56]. Thus, both phenomena secure additional information about the ambient atmosphere and can be utilized to improve gas detection.…”

“…This effect can be easily induced by UV LEDs irradiating the gas sensing layer (Figure 7). Numerous papers are presenting the detailed results of gas sensing modulated by UV light applied to different gas sensing layers [51][52][53][54][55][56][57][58]. A series of low-cost UV LEDs, emitting UV light within wavelet range 250÷355 nm is available on the market.…”

Amperometric Biosensor and Front-End Electronics for Remote Glucose Monitoring by Crosslinked PEDOT-Glucose Oxidase

“…Indeed, it has been shown that the behavior of the low frequency noise produced by a sensor depends, for the same DC reponse, on the nature of the chemical species interacting with the sensor. While a single sensor electronic nose based on FES as hypothesized in [22] is yet to be demonstrated, it is apparent that FES may allow increasing the selectivity of the sensor so as to distinguish in between…”

“…Furthermore, we report the design and development of 123 a wireless-powered system in which the potentiostat plays a 124 crucial role in the sensor conditioning and interfacing. Finally, 125 in order to investigate the feasibility of the application of 126 Fluctuation Enhanced Sensing (FES) techniques [22], [23] to 127 the amperometric sensor we developed, we designed a very 128 low noise potentiostat; we report on the very encouraging 129 results we have obtained, that may be regraded as a first step 130 toward the realization of future generation, highly sensitive 131 and selective sensor systems.…”