Evaluate the potential utilisation of B3S monolayer as a novel formaldehyde gas sensor.

It is crucial to identify an efficient system for the sensing of formaldehyde (FD). The feasibility of utilising a B₃S monolayer (B₃SML) detector of FD was evaluated by analysing the adsorption, optical properties, gas-sensing behaviour, and electronic properties of FD and other gas molecules on the B₃SML under density functional theory (DFT). The pristine B₃SML was found to have satisfactory sensing toward FD molecules. The analysis of the adsorption mechanisms, geometric systems, adsorption energy, electronic and optical properties, charge transfer, and electron density differences revealed that the B₃SML could potentially serve as an FD detector. It can be said that the B₃SML is a promising sensor for detecting FD molecules. The present study contributes to the existing knowledge of gas-surface interactions and helps develop 2D sensor structures to detect FD gas molecules. [ABSTRACT FROM AUTHOR]