Two-dimensional In 2 S 2 Se/In 2 Se 3 vdWH: solar cell material with high power conversion efficiency

Abstract Facing the energy shortage and environmental pollution, the solar-cell application is becoming increasingly widespread. Single-layer (SL) In 2 Se 3 is a famous two-dimensional (2D) semiconductor for strong visible absorption. However, its solar cell application has not been thoroughly studied, due to the lack of acceptor materials. Using first-principles calculations, this manuscript systematically investigates the structural, electronic, and power conversion efficiency ( PCE ) properties of In 2 S 2 Se/In 2 Se 3 van der Waals heterojunction (vdWH), where SL In 2 S 2 Se acts as an acceptor material based on the work function. The electronic band structure reveals that In 2 S 2 Se/In 2 Se 3 vdWH maintains a type-II band alignment under both biaxial and vertical strains, which is quite helpful for the carrier separation. In 2 S 2 Se/In 2 Se 3 vdWH achieves a solar conversion efficiency of 16.52%, suggesting its great perspective as a solar cell material.