Aldehyde adsorption studies on α‑arsenic phosphorus monolayer – A first-principles investigation

In recent days, researchers concentrate on elemental monolayer materials owing to their superior stability, sensitivity, and selectivity towards air contaminants. Besides, one example of two-dimensional (2D) material is the α‑arsenic phosphorus monolayer (α-AsP) which resembles black phosphorene and find its use in gas sensors and electronic devices owing to its extremely high carrier mobility. In the current work, we deployed stable α-AsP as a base material for the detection of formaldehyde and acetaldehyde. Initially, the stability and the electronic properties of the bare α-AsP are confirmed based on formation energy, ab initio molecular dynamics, phonon band structure, band structure, and PDOS (projected density of states) map. The band gap of α-AsP is computed to be 2.042 eV. Furthermore, the interaction of formaldehyde and acetaldehyde on α-AsP is examined based on band gap, charge transfer, and adsorption energy. The adsorption energies are observed in the scope of −0.277 eV to −0.497 eV, which falls in the physisorption regime. In addition, the adsorption and desorption behaviour of formaldehyde and acetaldehyde can be tailored by applying external strain. Thus, based on the results, we suggest that the α-AsP monolayer is a suitable material for sensing the formaldehyde and acetaldehyde.