Theoretical Exploration of C4F7N Decompositions on GeSe Monolayers for Gas Sensing Based on DFT Method

On account of its superior insulating perfor-mance and low global warming potential (GWP), C4F7N has been the focus of replacing SF6. Based on density functional theory, the adsorption mechanism and electrical char-acteristics of GeSe monolayer towards C4F7N decomposition species (COF2, CF4, CF3CN and C2F6CN) are explored to investigate the feasibility of GeSe gas sensors. Compared with other decomposition products, GeSe monolayers are more capable of capturing for C2F6CN, as evidenced by the smallest band gap (0.781 eV) and the highest adsorption energy (-0.427 eV). The adsorption behaviors lead to a larger GeSe band gap and thus a decrease in the conductivity of the adsorption system. The adsorption types of GeSe for four gases are all physical adsorption and can have good desorption properties at room temperature (298 K) with the adsorption capabilities: C2F6 CN>CF3CN>COF2>CF4. Theoretically, GeSe monolayers can be used to create a novel gas sensor for and industrial application, which can be utilized to monitor and diagnose high-voltage insulated equipment in real time.