First-principle study on monolayer and bilayer SnP₃ sheets as the potential sensors for NO₂, NO, and NH₃ detection

Layered SnP₃ sheets have recently been predicted as interesting 2D material with many potential applications. In the present work, first-principles calculations were performed to investigate the possibility of layered SnP₃ sheets as a candidate for detecting pollutant gases (CO, CO₂, H₂S, NH₃, NO, and NO₂). Our results indicate that CO, CO₂, H₂S molecules are all physisorbed on SnP₃ sheets with an adsorption energy of 0.116-0.363 eV. On the other hand, the strong interactions of NH₃, NO, and NO₂ and SnP₃ are found based on the moderate adsorption energy (around 1 eV for NO₂) and large charge transfer. The monolayer SnP₃ shows a higher affinity to these molecules than bilayer one. The chemisorption of NH₃, NO, and NO₂ molecules on layered SnP₃ sheets could efficiently evoke the electrical signal, and show short recovery time for NH₃, NO, and NO₂ capture. The work function calculations exhibit significant responses to the NH₃ and NO₂ molecules. Our results proposed that SnP₃ sheets could be utilized as a gas sensor for NO, NO₂, and NH₃, and extend the potential applications of 2D SnP₃ sheets.