Two-dimensional layered Janus-In2SeTe/C2N van der Waals heterostructures for photocatalysis and photovoltaics: first-principles calculations

Abstract

Constructing two-dimensional (2D) van der Waals heterostructures (vdWHs) with type-II band alignments has recently emerged as a promising strategy to obtain desirable optoelectronic devices. In this work, by density functional theory calculations we systematically investigate the stabilities, band structures and potential photocatalytic and photovoltaic properties of the vdWHs fabricated by combining 2D Janus-In₂SeTe with a C₂N monolayer. Herein, two types of Janus-In₂SeTe/C₂N vdWHs are considered: TeIn₂Se/C₂N and SeIn₂Te/C₂N heterostructures. The calculation results show that these systems possess direct gaps, type-II band alignments, low exciton binding energies, high carrier mobilities with asymmetry and strong light-harvesting ability in the UV-visible region. Remarkably, the band-edge positions of both the vdWHs perfectly straddle the water redox potential energies at certain pHs, enabling them to be very promising photocatalysts for overall water splitting. Besides, the power conversion efficiency can be as high as 18.25% and 21.47% for TeIn₂Se/C₂N and SeIn₂Te/C₂N vdWHs, respectively. These extraordinary properties render Janus-In₂SeTe/C₂N vdWHs to have great potential applications in the fields of clean and sustainable energy.