Detection of low levels of NO2 with electrospun tin dioxide nanofibers based sensors

Resistive sensors based on electrospun tin oxide nanofibers have been deposited onto micromachined silicon substrates to detect low nitrogen dioxide (NO2) concentrations in air. Solution precursors for the electrospinning were based on polyvinyl alcohol (PVA) and tin chloride dihydrate (SnCl2·2H2O). The sensors have been doped with gold and palladium in order to improve their sensing characteristics. The deposits were calcinated in air at 500 °C for 4 h to eliminate PVA and cause metal oxidation. The sensors were characterized from room temperature to 325 °C against low NO2 concentrations. High responses were obtained even at low temperatures.