Two-dimensional Sc2CCl2/SiS2 van der Waals heterostructure with high solar power conversion efficiency

Two-dimensional (2D) heterostructures are effective devices for converting solar energy into electrical energy. However, the highly efficient ones are difficult to screen. Here, we construct four configurations of 2D heterostructures by using Sc2CCl2 and SiS2 monolayers. On the basis of the first-principles calculations, we optimize geometrical structures, confirm the energy and thermal stabilities, calculate the electronic properties and optical absorptions, determine the solar power conversion efficiency (PCE), and explore the effect of strain engineering. The results indicate that the four configurations exhibit similar type-II band alignments with direct bandgaps, and the built-in electric fields support the electron transfer from the Sc2CCl2 monolayer to the SiS2 one. In addition, the highest predicted PCE of the configurations can reach 23.20%, which can be attributed to the small conduction band offset with a favorable bandgap of 1.49 eV that leads to excellent optical absorption in the range of visible and ultraviolet lights. These findings provide theoretical support for developing efficient solar cells and photodetectors by employing the Sc2CCl2/SiS2 heterostructure.