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.