First-principles studies of the SCl₂ adsorption on the doped boron phosphide monolayer

Sulfur dichloride (SCl₂) molecules form a harmful substance; however, it is widely used in the industry as insecticide and in organic synthesis. In contact with water, these molecules produce other toxic and corrosive gases. Therefore, it is important to remove them from the environment. In this work, we have studied the boron phosphide (BP) monolayer (ML) doped with metal atoms to be considered as a sensor material for the detection of sulfur dichloride (SCl₂) molecules. Studies are done by applying the density functional theory (DFT) according to the PWscf code of the Quantum ESPRESSO, using the projector-augmented-wave (PAW) method within the framework of the generalized gradient approximation (GGA) with the PBE parameterization. The results obtained indicate weak interactions between the SCl₂ molecule and the pristine BP monolayer. However, after metal-doping (with atoms of: Ga, In, N and As) the interactions between the SCl₂ molecule and the ML was increased, as expected. Parameters such as the adsorption energy (E_ad), work function (Ф), Bandgaps (E_g), recovery time (τ), electronegativity (χ) and chemical potential (μ) have been analyzed. The results suggest that the metal-doped BP monolayer may be a promising sensing material for gas sensor devices to detect SCl₂ molecules.

The SCl₂-metal-doped BP ML has been investigated using DFT calculations as implemented in the PWscf code of the Quantum ESPRESSO, and using PAW pseudopotential within the framework of the GGA-PBE and energy cutoff of 40Ry. The force components were smaller than 0.05 eV/Å and the Grimme-D2 scheme was considered. The Brillouin zone was sampled using a Monkhorst-Pack grid of 5 × 5 × 1 and 17 × 17 × 1 k-points for structural relaxations and electronic-properties calculations.