V2O5 nanofibres: novel gas sensors with extremely high sensitivity and selectivity to amines

Chemiresistor-type gas sensors were fabricated by depositing vanadium pentoxide (V2O5) nanofibres from aqueous suspension onto silicon substrates. Electrical contact was made through gold electrodes. Due to the sufficiently high conductivity of the fibres, the sensors could be operated at room temperature. Extremely high sensitivity was measured for 1-butylamine (limit of detection (LOD) below 30 ppb) and moderate sensitivity for ammonia. In contrast, only very little sensitivity was observed for toluene and 1-propanol vapours. The sensitivity to 1-butylamine increased linearly when increasing the relative humidity (rh) of the carrier gas from 0 to 60%. Contacting the fibres with either top or bottom electrodes dramatically changed the response characteristics. Based on these results, the sensing mechanism is discussed in terms of intercalation of the amine into the layered structure of the nanofibres and sorption at the nanofibre/electrode interface.