First-principles study of SO2 sensors based on phosphorene and its isoelectronic counterparts: GeS, GeSe, SnS, SnSe

Highlights: • The structure and electronic properties of the SO₂ adsorbed on phosphorene and its isoelectronic counterparts are studied. • The SO₂ molecule serves as a strong electron acceptor to the five substrates. • The SO₂ adsorption modified remarkably the electronic properties of the five substrates. Phosphorene and its isoelectronic counterparts, such as GeS, GeSe, SnS and SnSe monolayers, show great potential in electrical and sensing applications. Here, we study the SO₂ sensing properties of phosphorene and its isoelectronic counterparts by first-principles calculations. Results predict that the SO₂ molecule as electron acceptor holds high adsorption strength with the five monolayer substrates, especially for SnS and SnSe monolayers. Moreover, the electronic properties of the five substrates can be modified by the SO₂ molecule, together with distinct charge transfer, rendering them promising for application as a high-performance gas sensor.