Fast recovery and ultrasensitive net-graphene sensor for monitoring SF₆ decomposition by-products

Power industry insulator sulfur hexafluoride (SF₆) has excellent dielectric properties. However, SF₆ decomposes into by-products over time, making their detection essential for power device evaluation and fault prevention. Recently, 2D materials, especially carbon-based ones, have become excellent gas sensing platforms, expected to lead the next generation of sensors. Because graphitic materials and SF₆ decomposition products have weak van der Waals interactions, functionalization has been the most promising way to improve surface-molecule interactions, but it also presents experimental challenges. We propose monitoring SF₆ degradation with a pristine net-graphene nanosensor to address these issues. Here, density functional theory and non-equilibrium Green's functions methods are used to study the interaction between net-graphene device and gas-insulated switchgear atmosphere gas (SF₆, CO₂, N₂, H₂O, and O₂), as well as the decomposition products of SF₆. These molecules are physisorbed on net-graphene, causing p-type doping in the device. The system's conductance is modulated by molecule-net-graphene interactions, allowing target molecule detection and identification. We propose a field-effect device that can sense SO₂ and H₂S without cross-selectivity and with a fast recovery time. It is also resistant to O₂ and H₂O degradation. We found that net-graphene is a promising nanomaterial for real-time monitoring of power industry SF₆ decomposition by-products.