Out-of-plane polarization modulated band alignments in-InX/-InX(X = S and Se) vdW heterostructures.

The construction of two-dimensional (2D) van der Waals (vdW) heterostructures is an effective strategy to overcome the intrinsic disadvantages of individual 2D materials. Herein, by employing first-principles calculations, the electronic structures and potential applications in the photovoltaic field of the-InX/-InX(X = S and Se) vdW heterostructures have been systematically unraveled. Interestingly, the band alignments of-InS/-InS,-InSe/-InSe, and-InSe/-InSheterostructures can be transformed from type-I to type-II by switching the polarization direction of-InXlayers. It is highlighted that the light-harvesting ability of the-InX/-InXvdW heterostructures is significantly higher than the corresponding monolayers in nearly the entire visible light region. Interestingly, type-II-InS/-InSe↓ heterostructure can achieve the power conversion efficiency of 17.9%, where the-InSelayer acts as a donor and the-InSlayer displays as the acceptor. The present research not only provides an in-depth understanding that the out-of-plane polarization of-InXmonolayers can efficiently modulate the band edge alignment of the-InX/-InXvdW heterostructures, but also paves the way for the application of these heterostructures in the field of photovoltaics and optoelectronics.