Two-dimensional MoSSe/g-GeC van der Waals heterostructure as promising multifunctional system for solar energy conversion

Abstract Developing highly efficient photocatalysts for hydrogen/oxygen evolution reaction (HER/OER) and high-performance photovoltaic devices are desirable for solar energy applications. However, it still remains challenging to design an ideal multifunctional material for these purposes. Here, we propose the MoSSe/g-GeC heterostructure that can both realize overall water splitting reaction and serve as a potential candidate for solar cell. The first-principle calculations reveal that the MoSSe/g-GeC heterostructure possesses type-II band alignment, efficient charge separation, and noticeable visible-light adsorption, which supports its good photoelectronic performance. Applying appropriate strain can further promote the photocatalytic and photovoltaic properties of the MoSSe/g-GeC heterostructure. Especially, 4% compressive strain reduce the Gibbs free energy change of HER/OER to 0.01 eV/1.98 eV by changing interfacial charge transfer. While under 2% tensile strain, the power conversion efficiency of the MoSSe/g-GeC heterostructure is improved by around 35%. Our results indicate that MoSSe/g-GeC heterostructure is a promising multifunctional material for solar harvesting and contribute to developing more relevant systems.