Cu-Doped MoSe(2) Monolayer: A Novel Candidate for Dissolved Gas Analysis in Transformer Oil

[Image: see text] Dissolved gas analysis (DGA) in transformer oil is a workable approach to evaluate the operation status of transformers. In this paper, we proposed a Cu-doped Se-vacancy MoSe(2) (Cu-MoSe(2)) monolayer as a promising sensing material for DGA based on first-principles theory. Three typical dissolved gases, namely, CO, C(2)H(2), and C(2)H(4), are the representatives to investigate the potential of the Cu-MoSe(2) monolayer upon their adsorption and sensing. Our results indicate that Cu-doping causes strong n-doping for the Se-vacancy MoSe(2) monolayer, and the Cu-MoSe(2) monolayer exhibits strong chemisorption the three gas molecules, with a calculated adsorption energy (E(ad)) of −1.25, −1.06, and −1.16 eV, respectively. Such strong interactions lead to remarkable changes in the electrical conductivity of the Cu-MoSe(2) monolayer, allowing its application as a resistance-type sensor. Besides, work function (WF) analysis shows the potential of the Cu-MoSe(2) monolayer as a promising field-effect transistor sensor as well. It is our hope that our work can stimulate more leading-edge studies of the TM-doped MoSe(2) monolayer for sensing applications in many fields.