DFT study on Al/Sn-decorated arsenene: chemical bonding and adsorption of hexanal.

Herein, DFT calculations were performed to investigate various properties of Al/Sn-decorated arsenene, including its electronic structure, magnetism, and hexanal sensing. Three main systems were examined: pristine arsenene (p-As), aluminum (Al)-decorated arsenene (Al-As), and tin (Sn)-decorated arsenene (Sn-As). Results showed that both decorated systems exhibit magnetism in the ground state. The introduction of Al/Sn atoms significantly alters the electronic structure of arsenene by inducing defect-level states within the band gap. Al-As showed metallic characteristics, and Sn-As exhibited a small band gap. The strength and nature of chemical bonding between the X (X = Al and Sn) and As atoms were evaluated using COHP and ELF analysis. It was found that the X-As bond exhibited a mixed covalent and ionic character. Finally, the adsorption of a volatile organic compound (VOC), hexanal (HL), was investigated. We found that HL was weakly adsorbed on p-As and Sn-As. However, chemisorption was observed on Al-As due to a significant charge transfer through p-p overlapping. Thus, Al-As can be considered a promising candidate for HL sensing.