High Sensitivity and Selectivity of AsP Sensor in Detecting SF₆ Decomposition Gases

The sensing properties of monolayer arsenic phosphorus (AsP) for the adsorption of SF₆, H₂O, O₂, and SF₆ decomposition gases (SO₂ and H₂S) are theoretically investigated by the first-principle calculations. We calculate the adsorption energy, equilibrium distance, Mulliken charge transfer, and electron localization function (ELF) to explore whether AsP is suitable for detecting SF₆ decomposition gases. By comparing the adsorption performance of SF₆, H₂O, O₂, and H₂S gases, we have revealed that the SO₂ gas molecules could form stable chemisorption with AsP monolayer. The results demonstrate that AsP is highly sensitive and selective to SO₂ gas molecules with robust adsorption energy and apparent charge transfer. Furthermore, the current-voltage (I-V) curves reveal that only the adsorption of SO₂ can largely modify the resistance of AsP. Our results show that gas sensors based on AsP monolayer could be better than that of black phosphorene (BP) to diagnose the state of online gas-insulated switchgear (GIS).