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

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.