An ab initio study of two-dimensional anisotropic monolayers ScXY (X = S and Se; Y = Cl and Br) for photocatalytic water splitting applications with high carrier mobilities

Fei-Yang Xu; Yu Zhou; Tian Zhang; Zhao-Yi Zeng; Xiang-Rong Chen; Hua-Yun Geng

doi:10.1039/d1cp05369h

An ab initio study of two-dimensional anisotropic monolayers ScXY (X = S and Se; Y = Cl and Br) for photocatalytic water splitting applications with high carrier mobilities

Phys Chem Chem Phys. 2022 Feb 9;24(6):3770-3779. doi: 10.1039/d1cp05369h.

Authors

Fei-Yang Xu¹, Yu Zhou², Tian Zhang³, Zhao-Yi Zeng⁴, Xiang-Rong Chen¹, Hua-Yun Geng⁵

Affiliations

¹ Institute of Atomic and Molecular Physics, College of Physics, Sichuan University, Chengdu 610065, China. xrchen@scu.edu.cn.
² Department of Physics, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China.
³ College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, China.
⁴ College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 400047, China. zhaoyizeng@cqnu.edu.cn.
⁵ National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, CAEP, Mianyang 621900, China.

PMID: 35081609
DOI: 10.1039/d1cp05369h

Abstract

Recently, metal oxyhalides have been broadly studied due to their hierarchical structures and promising functionalities. Herein, a thorough study of newly modeled monolayers ScXY (X = S and Se; Y = Cl and Br), a class of derivates of ScOBr monolayers, was conducted using first-principles calculations. We theoretically confirm that these ScXY monolayers are mechanically, dynamically, and thermally stable. Young's modulus and Poisson's ratio calculated for all these ScXY monolayers obviously exhibit anisotropic properties. All these monolayers are indirect-gap semiconductors with bandgaps in the range of 2.35-3.18 eV, and their conduction band minimum (CBM) and valence band maximum (VBM) can straddle the reduction and oxidation potential of water very well, respectively. Particularly, ScSeCl and ScSeBr monolayers have the most propitious bandgaps and band alignments to be used as promising photocatalysts, and the predicted carrier mobility is much larger than that of many other two-dimensional materials. Moreover, the predicted anisotropic carrier mobilities and indirect bandgaps will diminish the recombination and facilitate the migration of photo-generated electron and hole pairs. Moreover, biaxial strain (-5% to 5%) effects on the band alignments and bandgaps are discussed. Our findings highlight that ScSeCl and ScSeBr monolayers are envisioned to act as promising photocatalytic and photoelectronic materials with anisotropic ultrahigh carrier mobilities.