Intriguing optical and photocatalytic properties of pentagonal penta-PtPS, -PtPSe and -PtPTe monolayers: A first-principle study

Abstract

Two-dimensional materials have demonstrated outstanding electronic, optical, and photocatalytic characteristics. In this article, the physical properties of pentagonal-like structure penta-PtPX (X = S, Se, Te) monolayers are systematically investigated by employing density functional theory. Phonon spectra and ab initio molecular dynamics simulations confirmed that these systems are thermodynamically stable. The hybrid HSE06 functional demonstrated that the PtPX monolayers are indirect band gap semiconductors, having band gap of 2.85 eV, 2.69 eV, and 2.14 eV for PtPS, PtPSe, and PtPTe respectively. The optical properties calculated using GW0+BSE approach reveal strong anisotropic absorption along x- and y-directions and the optical transitions are dominated by excitons. High absorbance in the visible and ultraviolet light region is observed, and the excitonic peaks are red shifted for heavy chalcogens. Furthermore, the photocatalytic study show that the PtPX monolayers can oxidize H2O/O2 to O2 and reduce H+ to H2, similar to the PdPX (X = S, Se, Te) monolayers. Our results suggest that the PdPX and PtPX (X = S, Se, Te) monolayers have potential for optoelectronic and photovoltaic devices, and are promising photocatalysts for water splitting reaction.