Highly sensitive response of solution-processed bismuth sulfide nanobelts for room-temperature nitrogen dioxide detection.

Low dimensional nanomaterials have emerged as candidates for gas sensors owing to their unique size-dependent properties. In this paper, Bi2S3 nanobelts were synthesized via a facile solvothermal process and spin-coated onto alumina substrates at room temperature. The conductometric devices can even sensitively response to the relatively low concentrations of NO2 at room temperature, and their sensing performance can be effectively enhanced by the ligand exchange treatment with inorganic salts. The Pb(NO3)2-treated device exhibited superior sensing performance of 58.8 under 5ppm NO2 at room-temperature, with the response and recovery time of 28 and 106s. The competitive adsorption of NO2 against O2 on Bi2S3 nanobelts, with the enhancement both in gas adsorption and charge transfer caused by the porous network of the very thin Bi2S3 nanobelts, can be a reasonable explanation for the improved performance at room temperature. Their sensitive room-temperature response behaviors combined with the excellent solution processability, made Bi2S3 nanobelts very attractive for the construction of low-cost gas sensors with lower power consumption.