Adsorption and sensing performances of transition metal (Pd, Pt, Ag and Au) doped MoTe2 monolayer upon NO2: A DFT study

Highlights: • Pt, Pd, Ag and Au-doping behaviors on MoTe₂ monolayer is expounded. • Adsorption performance of TM-MoTe₂ monolayer to NO₂ is fully analyzed. • DCD and EDD are considered to understand the charge-transfer behavior. • DOS, BS and FMO are used to understand the electronic behavior and sensing mechanism. Using density functional theory (DFT), the Pd, Pt, Ag and Au dopants are selected as the representatives to study the transition metal (TM)-doping behavior on the pristine MoTe₂ monolayer and related NO₂ sensing behavior. It is found that Pd and Pt adatoms prefer to be trapped through the T_Mo site, while Ag and Au dopants prefer to the T_H site. The NO₂ molecule behaves as electron-acceptor withdrawing charges from the TM-MoTe₂ monolayer, based on the Hirshfeld analysis, and NO₂ adsorption causes p-doping for Pd- and Pt-doped MoTe₂ monolayer, and causes n-doping for Ag- and Au-doped MoTe₂ monolayer, which decreases the bandgaps in the former two systems and increase the bandgaps in the latter two systems. Our calculations not only give an insight into the physicochemical property of TM-MoTe₂ monolayer, but also elucidate their promising potential as novel NO₂ sensors.