Tunable long-lived exciton lifetime and high carrier mobilities in Group III A elements doped two-dimensional blue phosphorene: A time domain <i>ab initio</i> study

In this Letter, we combine first-principles calculations with the non-adiabatic molecular dynamics (NAMD) method to investigate the photocatalytic and excited-state properties of blue phosphorene (BlueP). Doping with Group III A elements not only maintains an appropriate bandgap and band edge positions for photocatalytic water splitting but also converts the indirect bandgap of BlueP to a direct bandgap, significantly enhancing photon absorption efficiency. The dopants effectively improve optical absorption in the visible and ultraviolet light regions, potentially enabling a solar-to-hydrogen conversion efficiency of 22.3% in the photocatalytic water splitting process. In NAMD calculations, we consider the dynamics of the electron–hole pair recombination process between the valence band maximum and conduction band minimum. We demonstrate the regulatory impact of dopant elements, temperature, and non-adiabatic coupling strength on the exciton lifetime of doped BlueP through ab initio molecular dynamics and NAMD methods. This study reveals the relationship between the charge transfer mechanism and non-adiabatic coupling in low-dimensional materials, offering valuable insights into the excited-state properties of optoelectronic materials. Ultimately, our findings contribute to the development of tunable, long-lived exciton lifetimes and high carrier mobilities in doped BlueP, which hold significant potential for photocatalytic water splitting to generate hydrogen.