Out-of-plane polarization modulated band alignments inß-In2X3/α-In2X3(X = S and Se) vdW heterostructures.

ABSTRACT

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 theß-In2X3/α-In2X3(X = S and Se) vdW heterostructures have been systematically unraveled. Interestingly, the band alignments ofß-In2S3/α-In2S3,ß-In2Se3/α-In2Se3, andß-In2Se3/α-In2S3heterostructures can be transformed from type-I to type-II by switching the polarization direction ofα-In2X3layers. It is highlighted that the light-harvesting ability of theß-In2X3/α-In2X3vdW heterostructures is significantly higher than the corresponding monolayers in nearly the entire visible light region. Interestingly, type-IIß-In2S3/α-In2Se3↓ heterostructure can achieve the power conversion efficiency of 17.9%, where theα-In2Se3layer acts as a donor and theß-In2S3layer displays as the acceptor. The present research not only provides an in-depth understanding that the out-of-plane polarization ofα-In2X3monolayers can efficiently modulate the band edge alignment of theß-In2X3/α-In2X3vdW heterostructures, but also paves the way for the application of these heterostructures in the field of photovoltaics and optoelectronics.