Electronic, photocatalytic, and optical properties of two-dimensional boron pnictides

By employing first-principles calculations, we investigate the stabilities, quasi-particle band structures, and photocatalytic and optical properties of monolayer boron pnictides. Calculations indicate that monolayer boron pnictides have highly thermal stabilities verified by molecular dynamics, appreciable direct bandgaps, and good optical absorptions in the visible and near-infrared ranges. In addition, the relatively small exciton binding energies are also observed in the three systems, facilitating the separation of photogenerated electrons and holes. More interestingly, monolayer boron phosphide satisfies the criteria of photocatalyst for water splitting, and its photocatalytic performance can be further enhanced by applying biaxial tensile strain. Our researches provide valuable insight for finding monolayer boron pnictides applied in optoelectronics and photocatalytic water splitting.