Tunable power conversion efficiency and excellent infrared absorption of BAs/WSe2 vdW heterostructures with different stacking modes

Constructing van der Waals (vdW) heterostructure by stacking structurally similar two-dimensional materials is a practical approach to achieve desirable properties. Two stacking forms of BAs/WSe2 vdW heterostructures are discussed, one possessed excellent optical absorption properties in the near infrared range and the other exhibited extremely high power conversion efficiency (PCE) under biaxial strain. Different stacking forms exhibit distinct band alignment and optical characteristics, and both of them are able to respond well to external stress. The vdW heterostructure with type-I band alignment not only demonstrates fantabulous optical absorption in the ultraviolet and visible but also has an optical absorption coefficient of 105 orders of magnitude in the near infrared, which has great potential for use in photothermal therapy and biocatalysis. At 3% biaxial strain, the PCE of the BAs/WSe2 heterostructure with type-II band alignment rose from 4.48% to 20.90% (increased by 366.52%), which could be used as a raw material for solar cells. The results provide potential candidates for next-generation photothermal therapeutic materials, and raw materials for solar cells.