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

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. 2D ternary nitride XNY is a direct band gap semiconductor with thermodynamic, molecular dynamics and mechanical stability, 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. [Display omitted] •Proposed a high-stability direct band gap semiconductor material: 2D Ternary Nitrides XNY (X ​= ​Ti, Zr, Hf; YF, Cl, Br).•XNY has anisotropic mechanical and optical properties that it can be applied to direction-dependent devices.•XNY has absorption of visible light and near-ultraviolet light, indicating that it can be applied to photoelectric detection.•ZrNF and HfNCl have stable and large band edge position alignment, which provide candidates for visible light-catalyzed water splitting.