2D ternary nitrides XNY (X=Ti, Zr, Hf; Y[dbnd]F, Cl, Br) with applications as photoelectric and photocatalytic materials featuring mechanical and optical anisotropy: A DFT study

Abstract

Using density functional theory, we systematically studied the stability, electronic structure and optical properties of two-dimensional ternary nitrides XNY (X ​= ​Ti, Zr, Hf; YF, Cl, Br). Through phonon spectrum calculations and ab initio molecular dynamics simulations, we found that XNY is dynamic and thermodynamically stable. The calculated results of cohesive energy indicate the possibility of synthesis experimentally. XNY is a direct band gap semiconductor, and the band gap is larger than the 1.23 ​eV required for water splitting. In addition, XNY has anisotropic mechanical and optical properties. In addition, XNY has absorption of visible light, and the band-edge arrangement of ZrNF and HfNCl is feasible for water photo oxidation and photo reduction. These comprehensive properties make 2D ternary nitride XNY a candidate material for direction-dependent optoelectronic devices, and it is expected to be applied in the field of photo catalysis.