Monoelemental two-dimensional iodinene nanosheets: a first-principles study of the electronic and optical properties

Very recently, two-dimensional (2D) iodinene, a novel layered and buckled structure has been successfully fabricated (Qian et al 2020 Adv. Mater. 32 2004835). Motivated by this latest experimental accomplishment, for the first time we conduct density functional theory, first-principles calculations to explore the structural, electronic, and optical properties of monolayer, few-layer and bulk iodinene. Unlike the majority of monoelemental 2D lattices, iodinene is predicted to be an intrinsic semiconductor. On the basis of calculations using the generalized gradient approximation of Perdew-Burke-Ernzerhof for the exchange-correlation functional and the Heyd-Scuseria-Ernzerhof (HSE06) functional, it is shown that the electronic bandgap of iodinene decreases with increasing the number of atomic layers. Our HSE06 results reveal that the bandgap of iodinene decreases from 2.08 to 1.28 eV as the number of atomic layers change from one to five, highlighting the finely tunable bandgap. The optical study shows the monolayer has the ability to absorb a wide range of ultraviolet light, more than multilayers and bulk iodinene. As the number of layers increases, the absorption spectra exhibits a blue shift relative to monolayer iodinene. This study confirms the remarkable prospect for the application of iodinene in nanoelectronics and optoelectronics owing to its intrinsic semiconducting nature. © 2021 IOP Publishing Ltd.