Aniline oligomer-assisted exfoliation of MoS₂ nanosheets for high-performance room-temperature NO₂ gas sensing

Two-dimensional transition sulfides (TMDs) are ideal materials for room-temperature gas sensing due to their high carrier mobility at room temperature. Nevertheless, the inferior response and incomplete recovery of TMDs at room temperature hinder their development in the field of the most advanced gas sensors. Herein, we propose two-dimensional surface p-p heterojunctions constructed via organic conjugated molecules assisted stripping of molybdenum disulfide (MoS2) for high-performance room-temperature nitrogen dioxide (NO2) gas sensing. The aniline tetramer (TANI) was employed as an exfoliation-assistant reagent, adhering evenly to the surface of the exfoliated MoS2 nanosheets, and forming a good MoS2/TANI heterostructure. The sensor built with this heterostructure has a 28.5% response to 1 ppm NO2 at room temperature, outperforming a standalone MoS2 sensor by more than fourfold. The device still has a significant response even at NO2 concentrations as low as 30 ppb. Furthermore, the MoS2/TANI-3 heterostructure gas sensor also exhibits excellent repeatability, long-term stability, superior linearity, and good selectivity at room temperature. Above all, the proposed design technique, as well as the developed structures, can pave the way for the development of high-performance TMDs-based gas sensors.