Revealing a Highly Sensitive Sub-ppb-Level NO₂ Gas-Sensing Capability of Novel Architecture 2D/0D MoS₂/SnS Heterostructures with DFT Interpretation

Abstract

In this work, we use a chemical method to design novel 2D-material/0D-quantum dot (MoS₂/SnS) heterostructures. Furthermore, the unique 2D/0D heterostructure enhanced the NO₂ gas-sensing capability 3 times and increased the sensing recoverability by more than 90%. Advanced characterization tools such as SEM, TEM, XRD, and AFM confirm the formation of MoS₂/SnS heterojunction nanomaterials. Using AFM data, the average thickness of the MoS₂ layer was found to be 5 nm. The highest sensor response of 0.33 with good repeatability was observed at 250 ppb of NO₂. Sensing characterization reveals the ultra-fast response time, that is, 74 s, at 50 ppb of NO₂. The limit of detection for detecting NO₂ was also found to be very low, that is, 0.54 ppb, by using MoS₂/SnS heterostructures. The theoretical calculations based on density functional theory well corroborated and quantified the intermolecular interaction and gas adsorption on the surface of MoS₂/SnS.