Highly efficient room-temperature ethylene sensing with molybdenum based transition metal dichalcogenides

Detecting ethylene (C₂H₄) is essential across various domains, including agricultural logistics, fruit quality control, healthcare, and industry. However, effective C₂H₄ sensing poses significant challenges due to the molecule's non-polar nature and the requirement for ultra-high sensitivity at trace concentrations (parts-per-billion, ppb). Traditional C₂H₄ sensors often rely on costly, complex, and less portable techniques. In this study, we demonstrate the potential of two-dimensional (2D) molybdenum-based transition metal dichalcogenides (TMDs), including MoS₂, MoSe₂, MoTe₂, and their defective/surface-functionalized forms, as effective C₂H₄ sensors based on portable electrical transduction. Using a combination of theoretical approaches, including density functional theory (DFT), non-equilibrium Green's functions (NEGF), and thermodynamics analysis by Langmuir adsorption model, we explore the C₂H₄ sensing capabilities of the mentioned materials. Our findings indicate that pristine TMDs show limited adsorption affinity toward C₂H₄, but doping with elements such as silicon (Si), germanium (Ge), and tin (Sn) remarkably magnifies their adsorption. Specifically, Si-doped MoS₂, Ge-doped MoSe₂, and Sn-doped MoTe₂ exhibit strong covalent bonding with C₂H₄ through Si-C, Ge-C, and Sn-C interactions, triggering contrastive modulation of electronic transport upon C₂H₄ exposure. Among these, Si-doped MoS₂ demonstrates outstanding sensitivity and is capable of detecting C₂H₄ at ppb levels under ambient temperatures. It achieves a sensitivity of 77.9 % with an ultrafast recovery time of 3.79 × 10⁻² ms at 500.0 K, making it a prime candidate for advanced C₂H₄-sensing applications.