Density functional theory calculations of phenol-modified monolayer silicon nanosheets

摘要

Silicon nanosheets are one of most exciting recent discoveries, being a two-dimensional form of silicon that is only nanometers thick, with large lateral dimensions. A single atomic layer silicon nanosheet is known as silicene and can be grown with different surface terminations. It has been shown previously that organo-modified silicene can be synthesised with phenyl groups covalently bonded to both sides of the nanosheet, with hydrogen atoms terminating the under-coordinated silicon atoms. In this work, we use density functional theory calculations and ab initio molecular dynamics simulations to determine the effect of hydroxyl (OH) group substitutions on the phenyl-modified silicene. Different positions of the OH groups on the phenyl rings were modelled including ortho-, meta- and para- substituted positions. We found that the meta-substituted position was favoured, followed by the para- then ortho- substituted positions. Our ab initio MD simulations showed that the phenol groups will freely rotate on the nanosheet, aligning so as to form hydrogen bonds between adjacent phenol groups. The unique properties of this material could be useful for future electronic device applications.