First-principles study of the monolayer SnSSe for gas sensing applications

Abstract

Based on first-principles calculation, we investigated the properties of toxic gases (CO, H₂S, NH₃, NO₂, SO₂) adsorption on different sides of monolayer SnSSe. Results show that all the toxic gas molecules tend to adsorb on the hollow sites above Sn. The adsorption energies of all the gas molecules are negative, ranging from −0.1026 eV to −0.2494 eV, suggesting that the adsorption of the gases is spontaneous. We also calculated the charge transfer between the gas molecules and the SnSSe. The results showed that all the gas molecules were charge donors except NO₂. The recovery time of the adsorption of toxic gases on the monolayer SnSSe are also discussed through the transition state theory, and the results showed that the adsorption times of these gas molecules were below the millisecond level. Calculations of electronic properties show that the adsorption of NO₂, NH₃ changes the electronic structure of SnSSe near the Fermi level, while the remaining gases have little effect on the electronic structure of monolayer SnSSe near the Fermi energy level, demonstrates the potential of monolayer SnSSe for N-based gas detection. Our study is expected to provide theoretical guidance for the fabrication of SnSSe-based gas-sensitive sensor devices and performance improvement.