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

On account of its superior insulating performance and low global warming potential (GWP), C
₄
F
₇
N has been the focus of replacing SF
₆
. Based on density functional theory, the adsorption mechanism and electrical characteristics of GeSe monolayer towards C
₄
F
₇
N decomposition species (COF
₂
, CF
₄
, CF
₃
CN and C
₂
F
₅
CN) are explored to investigate the feasibility of GeSe gas sensors. Compared with other decomposition products, GeSe monolayers are more capable of capturing for C
₂
F
₅
CN, 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: C
₂
F
₅
CN>CF
₃
CN>COF
₂
>CF
₄
. 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.