A bifunctional GeC/SnSSe heterostructure for highly efficient photocatalysts and photovoltaic devices

Alongside highly efficient photocatalysts, high photovoltaic performance is also a key element for efficiently harvesting solar energy. Developing bifunctional materials which satisfy concurrently these two demands is an appealing strategy for solving the current serious energy and environmental issues. Based on first-principles and quantum transport calculations, we designed this kind of novel bifunctional material: Janus GeC/SnSSe van der Waals heterostructure (vdWH). We demonstrate that it is a highly efficient direct Z-scheme photocatalyst. However, unlike traditional direct Z-scheme photocatalysts, the GeC/SnSSe vdWH possesses a small energy separation between the low conduction band located in SnSSe and the high valence band residing in the GeC layer, which significantly fosters the interlayer charge transfer. Hence, its solar-to-hydrogen conversion efficiency reaches as high as 68.37%. Moreover, we also find that tensile strain promotes an astonishing increase in photovoltaic performance, e.g., 4% tensile strain leads to an increase of the photocurrent by 40%.

Automated summary

Efficient photocatalysts and high photovoltaic performance are important for solar energy harvesting. This study presents a novel bifunctional material, Janus GeC/SnSSe van der Waals heterostructure, which serves as a highly efficient direct Z-scheme photocatalyst. The study also reveals that tensile strain greatly improves the photovoltaic performance.