Fluctuation enhanced gas sensing with WO3-based nanoparticle gas sensors modulated by UV light at selected wavelengths

•Sensitivity and selectivity of WO3-based gas sensors can be improved by irradiation with ultraviolet light.•The wavelength of the UV light is important.•Fluctuation enhanced gas sensing improves the selectivity of gas detection upon UV irradiation. The sensitivity and selectivity of WO3-based gas sensors can be enhanced by UV-irradiation-induced modulation, especially if different wavelengths are employed. We used fluctuation-enhanced gas sensing, based on measurements of resistance fluctuations in the gas sensor, to study the effects of such modulation on the noise intensity for ambient atmospheres of synthetic air without and with additions of small amounts of ethanol, methane and formaldehyde. Our data confirmed that the method is energy efficient and can be applied to improve gas detection sensitivity and selectivity. The results are strongly dependent on the gaseous species, and a single UV-modulated WO3-based gas sensor discriminate between different gases.