Theoretical Study of Superhigh-Efficiency Janus WSSe/β-Te Non-Perovskite Heterojunction Solar Cells

The electronic structures and optoelectronic properties of heterostructure are closely related to the species of composed atoms and their relative position of the terminal surface at the interface. Here, we proposed a Janus WSSe/β-Te heterostructure for non-perovskite solar cells with super high power conversion efficiency (PCE). Considering that WSSe and β-Te layers can slide relatively, ten possible stacking configurations of Janus WSSe/β-Te heterostructure are designed, in which AB and AB* configurations are the most stable stacking. Taking AB stacking as an example, under the dual effect of slither and stress engineering, its theoretical PCE is as high as 23.64% because of its modest band gap, suitable relative band edge position, and high light absorption coefficient (∼106 cm–1). Strong orbital hybridization at the interface accelerates the migration of photogenerated electrons, effectively improving photovoltaic efficiency. Moreover, the solar-to-hydrogen efficiency of AB stacking can reach 14.6%, which is already larger than that of commercially available hydrogen production. Our findings provide an avenue to design productive heterojunctions for photovoltaic and photocatalytic applications.