Density Functional Theory Study of Two-Dimensional SnS₂ Doping for Detection of Hydrogen Sulfide

The efficient and rapid detection of toxic and combustible H 2 S released during industrial processes is extremely crucial. However, two-dimensional (2D) SnS 2 shows a weak interaction with H 2 S, leading to difficult detection. In this work, we use density functional theory (DFT) calculations to modify the SnS 2 monolayer by N, P, Ge, and Se doping and investigate the adsorption properties and gas-sensing mechanism of each doped SnS 2 . By analyzing the adsorption energy, charge density difference, band structure, and recovery time, we suggest that Ge and Se doping is detrimental to the detection of H 2 S. Significantly, N and P doping can efficiently strengthen the interaction between SnS 2 and H 2 S and simultaneously maintain the physisorption with the adsorption energy of −0.60 eV and −0.64 eV, leading to a suitable recovery time (5.64 × 10 –2 s and 1.20 × 10 –2 s). The H 2 S@N and P-SnS 2 systems exhibit significant band gap decreases (1.51 and 0.84 eV). Moreover, combined with nonequilibrium Green’s function (NEGF) method, the simulation of current–voltage characteristics further reveals their high sensitivity, reaching nearly 100%. Hence, the DFT and NEGF calculations in this work provide an efficient doping strategy to make 2D SnS 2 a highly reusable and sensitive gas sensor for the detection of H 2 S.