Adsorption of ethylene oxide on doped monolayers of MoS2: A DFT study

Abstract

Density functional theory (DFT) calculations have been performed to investigate the doping of Ti, Ni, Pd, Si, Ge, P, and Cl atoms into an S-vacancy of MoS2 monolayer, and its impact on the sensitivity toward ethylene oxide (EO). The results show that, pristine MoS2 is chemically inert toward EO, however, Ti, Ni, Pd, and Si doping facilitates a stronger binding with the molecule, and an enhanced charge transfer sufficient for detection. Furthermore, the electronic band gap of Ti, and Si doped MoS2 is shown sensitive toward EO, experiencing a 0.26 eV (22%) and 0.85 eV (51%) change upon adsorption, which suggests a second mode of detection. The investigation also illustrates that, in order to achieve stronger binding and adsorption-sensitive band gap the d-block doped MoS2 requires a strong pz/dz2 hybridization, while p-block doped layer requires an activation of the s subshell of the dopant.