A first-principles study of SOF₂ and SO₂F₂ adsorption onto PdSe₂-based monolayers: favorable sensitivity and selectivity by doping single Cu or Rh atom

In this first-principles study, we simulate the adsorption of SOF₂ and SO₂F₂ molecules on the pristine, Cu- and Rh-doped PdSe₂ monolayer, in order to explore their potentials as novel gas sensors for status evaluation of the SF₆-insulation devices. Single Cu or Rh atom is doped by the replacement of a Se atom within the PdSe₂ surface, with the formation energy of 0.40 and -0.62 eV, respectively. Compared with the weak interactions between the pristine PdSe₂ monolayer and two gas species with little potential for gas sensing application, Cu-PdSe₂ monolayer behaves stronger physisorption and Rh-PdSe₂ monolayer conduct more favorable chemisorption upon two gases. The adsorption characteristic, charge density difference, band structure and density of states of various adsorption configurations are systemically analyzed to understand the gas-surface interactions. Results indicate that Pd-PdSe₂ monolayer, rather than the Cu-doped counterpart, is a promising resistive gas sensor with good sensitivity and selectivity for detection of SOF₂ and SO₂F₂. The analysis of work function in gas adsorbed Cu- and Rh-PdSe₂ systems reveals their strong potential for the development of Schottky gas sensors upon two gases with high and tunable sensitivity and specificity. These findings in this work hold significant meanings for typical gas detection to evaluate the operational status of SF₆-insulated devices. It is hopeful that this work can stimulate more edge-cutting investigations on the PdSe₂-based gas sensor for application in some other fields.