Novel 2D HfTeS4 for water splitting with high visible-light absorption

Abstract

Currently, photocatalysts have got much attention due to its promising application prospect in clean and reusable resources. In this paper, we have disclosed a novel monolayer HfTeS4 through first-principles calculations and the great stability of the HfTeS4 monolayer has been proved based on the formation energy, phonon spectrum and ab initio molecular dynamics. The HfTeS4 monolayer displays a remarkable absorbance capacity of up to 7.5 × 105 cm−1 in visible light region and a high carrier mobility of 864 cm−2 V−1 s−1. Both visible light absorbance capacity and carrier mobility are about 4 times larger than these properties of MoS2. Meanwhile, the anisotropy of carriers is beneficial to improve the photo-catalytic efficiency. Furthermore, tunable bandgaps under biaxial strain engineering are also provided. The results show that HfTeS4 monolayer can meet the conditions of photocatalysis in the strain range from -5% to 1%. Moreover, we surprisingly find that the HfTeS4 multilayers have proper band edges and much better light absorption ability than the monolayer, which ismore suitable for practical application. Our research reveals that all these fascinating properties make both monolayer and multilayer HfTeS4 a promising candidate for photocatalytic applications.