Important considerations for effective gas sensors based on metal oxide nanoneedles films

Gas sensor devices based on either polycrystalline or nanoneedle tungsten oxide were deposited in situ on classical ceramic substrates via AACVD, and subsequently functionalized with gold nanoparticles via sputtering. The sensing properties of the films were tested to a wide range of analytes, revealing high responses to ethanol, hydrogen, and nitrogen dioxide, at low operating temperatures (≤250 °C), and a lack of response to carbon monoxide, ammonia, and hydrogen sulfide. In addition, the sensing responses to hydrogen and nitrogen dioxide, at 100 °C and 150 °C, were improved by using gold functionalized structures. Modest differences of the sensor response magnitude in polycrystalline, and nanoneedle films were observed, suggesting the need of special substrate platforms for effective application of nanostructured films in gas sensors devices.