The van der Waals Heterostructures MoS2/TeGaInX (X = S, Se, Te) for Optoelectronic and Photocatalytic Applications

Rising energy demands and environmental concerns are accelerating the shift to clean energy, with hydrogen technology emerging as one of the most promising solutions. In this study, the MoS2/TeGaInX van der Waals heterostructures (vdWHs) were thoroughly investigated for optoelectronic and photocatalytic applications using first-principles calculations. A significant interfacial potential drop leads to a strong internal electric field, which effectively suppresses carrier recombination and encourages the spatial separation of photogenerated electron–hole pairs. These vdWHs have favorable band edge potentials for overall water splitting at pH = 0, along with the exceptionally high carrier mobilities up to 104 cm2 V–1 s–1. The MoS2/TeGaInS, MoS2/SInGaTe, MoS2/TeGaInSe, and MoS2/TeInGaTe vdWHs exhibit remarkable solar-to-hydrogen (ηsth) efficiencies up to 30%, indicating their great potential for effective hydrogen production. Furthermore, the vdWHs show improved optical responses, such as substantial imaginary dielectric functions and high absorption coefficients up to 105 cm–1 in the visible-light spectrum, demonstrating superior light-harvesting capabilities. Overall, this work provides a deeper physical insight on Janus-based MoS2 heterostructures and offers valuable theoretical guidance for designing high-performance vdW-based photocatalytic and optoelectronic devices.