GeSe@SnS: stacked Janus structures for overall water splitting

Two-dimensional materials with an intrinsic electric field have recently emerged as a new class of photocatalysts with high efficiency. Currently, all research studies in this field focus on homogeneous materials. Using first-principles calculations, and nonadiabatic molecular dynamics, we show a promising way to achieve photocatalysts for overall water splitting based on stacked Janus structures. We demonstrate that stacking SnS and GeSe Janus structures leads to an electric field and excellent photocatalytic performance for overall water splitting. We reveal how the type of contact surface acts on the electrostatic potential and the dipole moment. Most importantly, the decomposition of water reaction in such a stacked Janus structure can proceed spontaneously under light irradiation. We also show that the recombination time of excitons for this system is 57 ps, indicating a relatively low dynamic rate for electron-hole recombination.