Highly sensitive and selective ammonia gas sensors based on PbS quantum dots/TiO2 nanotube arrays at room temperature

Abstract In the present work, PbS quantum dots/TiO 2 nanotubes arrays (PbS QDs/TiO 2 NTARs) are prepared by successive ionic-layer adsorption and reaction, which are used to fabricate the gas sensor. The gas sensing performance shows that PbS QDs/TiO 2 NTARs possess a good response towards ammonia gas at room temperature. PbS QDs/TiO 2 NTARs sensitized with 0.1 M concentration and 6 cycles possess the best gas response, and the gas response could reach 17.49 for 100 ppm ammonia with a detection limit of 2 ppm at room temperature. It also proves that PbS QDs/TiO 2 NTARs have a quite good selectivity towards ammonia compared with ethanol, methanol, acetone and toluene at room temperature. The enhanced sensing mechanism is also discussed.