Electronic, optical and photocatalytic properties of 2D penta-Pd₂Pt₂P₄X₂Y₂ (X ≠ Y = S, Se, Te) Janus monolayers: a first principles study

The remarkable structural features and versatile applications of two-dimensional (2D) Janus materials have received considerable attention in recent years, particularly in the field of electronic and optoelectronic, and photocatalysis. In this study, we employed density functional theory (DFT) to comprehensively investigate the structural, electronic, and optical and photocatalytic properties of penta-Pd₂Pt₂P₄X₂Y₂ (X ≠ Y = S, Se, Te) Janus monolayers. The phonon spectra and the ab initio molecular dynamic of these Janus monolayers confirm their Dynamics and thermal stability. The Pd₂Pt₂P₄X₂Y₂ monolayers are indirect semiconductors, with band gap values ranging from 1.63 to 2.25 eV, with HSE06 functional and have ultra-high carrier mobility obtained with deformation potential method. The optical properties calculated using GW₀ + BSE reveal high absorbance in the infrared, visible and ultraviolet light regions and have anisotropic absorption. The Exciton binding energies, calculated using the GW₀ band gap approach, range from 0.61 to 1.31 eV. Furthermore, the photocatalytic study shows that all the 2D Pd₂Pt₂P₄X₂Y₂ Janus monolayers can oxidize H₂O/O₂ to O₂ and reduce H⁺ to H₂. Additionally, these monolayers exhibit STH efficiencies ranging from 11.8 to 28.1%, exceeding the industrial target of 10%. These results suggest that the 2D Pd₂Pt₂P₄X₂Y₂ Janus monolayers have potential candidates for electronic and optoelectronic, photovoltaic and photocatalytic water splitting application.