The interlayer coupling modulation of a g-C 3 N 4 /WTe 2 heterostructure for solar cell applications.

Constructing van der Waals (vdW) heterostructures has been proved to be an excellent strategy to design or modulate the physical and chemical properties of 2D materials. Here, we investigated the electronic structures and solar cell performances of the g-C 3 N 4 /WTe 2 heterostructure via first-principles calculations. It is highlighted that the g-C 3 N 4 /WTe 2 heterostructure presents a type-II band edge alignment with a band gap of 1.24 eV and a corresponding visible light absorption coefficient of ∼10 6 cm -1 scale. Interestingly, the band gap of the g-C 3 N 4 /WTe 2 heterostructure could increase to 1.44 eV by enlarging the vdW gap to harvest more visible light energy. It is worth noting that the decreased band alignment difference resulting from tuning the vdW gap, leads to a promotion of the power conversion efficiency up to 17.68%. This work may provide theoretical insights into g-C 3 N 4 /WTe 2 heterostructure-based next-generation solar cells, as well as a guide for tuning properties of vdW heterostructures.