Band gap engineering of bulk and nanosheet SnO: an insight into the interlayer Sn-Sn lone pair interactions.

The effects of interlayer lone-pair interactions on the electronic structure of SnO are explored using density-functional theory. Our comprehensive study reveals that the band gap of SnO opens with the increase in the interlayer Sn-Sn distance. The effect is rationalized by the character of band edges which consist of bonding and anti-bonding states from interlayer lone pair interactions. The band edges for several nanosheets and strained double-layer SnO are estimated. We conclude that the double-layer SnO is a promising material for visible-light driven photocatalysts for hydrogen evolution.