S-Scheme Boron Phosphide/MoS₂ Heterostructure with Excellent Light Conversion Ability for Solar Cells and Water Splitting Photocatalysts

Abstract

Monolayer molybdenum disulfide (MoS₂) with a suitable direct band gap and strong optical absorption is very attractive for utilization in solar cells and photocatalytic water splitting. Nevertheless, the broader utilization of MoS₂ is impeded by its low carrier mobility and limited responsiveness to infrared light. To overcome these challenges, we constructed a variety of stackings for the boron phosphide (BP)/MoS₂ van der Waals heterostructure (vdWH), all of which display S-scheme band alignments except for the AC' stacking. The constituent BP monolayer has superior carrier mobility and strong infrared and visible light response, which makes up for the shortcomings of MoS₂. The study revealed that the AB stacking exhibits a remarkable power conversion efficiency of 22.27%, indicating its significant application prospect in solar cells. Additionally, the AB stacking also exhibits a promising application prospect in photocatalytic water splitting due to its suitable band structure, S-scheme band alignment, strong optical adsorption characteristic, high solar-to-hydrogen efficiency, and robust built-in electric field. Meanwhile, applying uniaxial tensile strains along the <i>x</i>-axis direction is more beneficial for photocatalytic water splitting. Hence, the AB-stacked BP/MoS₂ vdWH shows significant potential for use in both solar cells and photocatalytic water splitting. This work paves the way for exploring the application of S-scheme heterostructures in solar energy conversion systems.