Theoretical Analysis of the Geometrical Effects of Tilted/Horizontal MoS₂/WSe₂ van der Waals Heterostructures: Implications for Photoelectric Properties and Energy Conversion

The geometry effect is one of the effective methods to modulate the photoelectric properties of photovoltaic units. Herein, we investigate the geometry effect on the optical absorption and photoelectric conversion properties of nanosheet array-based tilted/horizontal MoS2/WSe2 van der Waals heterostructures based on the bond relaxation consideration and detailed balance principle. We find that the tilted/horizontal heterostructures exhibit excellent photoelectric properties compared to those of horizontal/horizontal cases owing to the small light reflectivity in the nanosheet array. Especially, the MoS2/WSe2 heterostructure with type-B is the optimal structure for energy harvesting as the optimal power conversion efficiency (PCE) can be further achieved by modulating the sheet size and tilt angle, and its PCE can be up to 12.60% at θ = 62° and D1 = 9.7 nm in the case of L1 = D2 = 100 nm. Our results provide insights into optimizing the nanodevice performances of TMDs-based heterostructures.