Ab-initio Study Based Understanding of Pnictogen Trihydrides Adsorption on WS2 Monolayer

Abstract

The work in this paper mainly focuses on the adsorption possibility of some pnictogen trihydride based highly toxic gas molecules such as NH3, PH3, AsH3, and SbH3 towards 2D layered transition metal dichalcogenides (TMDs) based pristine WS2 monolayer using density functional theory incorporated with QuantumATK atomistic toolkit. To explore the sensing performance and electronic properties of pristine WS2 monolayer towards above mentioned gas molecules, geometrical parameters, adsorption energy, charge transfer mechanism, adsorption distance, and projected density of states were studied and discussed. The outcome of the study suggested that the WS2 monolayer allowed all gases to be adsorbed and the comparative adsorption probability was found to be maximum for NH3 gas molecule with highest adsorption magnitude of -0.308 eV. The maximum charge transfer was found in NH3-WS2 interaction. The second most adsorbed gas molecule on WS2 monolayer was PH3. The lowest gas adsorption possibility was found for SbH3 molecule with the adsorption magnitude of -0.185 eV which was around 66% lesser than the adsorption possibility of NH3 molecule on WS2 monolayer. SbH3 gas molecule was adsorbed with highest adsorption distance among other pnictogenic gas molecules. No covalent bonds were formed after adsorption of gas molecules on WS2 monolayer where the adsorptions mainly occurred due to the association of weak van der Waals forces.