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

Abstract

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.