Evolution of Intrinsic Vacancies and Prolonged Lifetime of Vacancy Clusters in Black Phosphorene

TL;DR

This study combines first-principles calculations and kinetic Monte Carlo simulations to analyze vacancy evolution in black phosphorene, revealing stable vacancy clusters that impact its structural and catalytic properties.

Contribution

It uncovers the formation, stability, and slow disappearance of vacancy clusters in phosphorene, providing insights for structural repair and catalytic applications.

Findings

Isolated monovacancies are highly mobile and tend to form stable pairs.

Approximately 80% of vacancies remain after two years at room temperature.

Stable vacancy clusters can serve as potential catalysts.

Abstract

Due to the relatively low formation energies and highly mobile characteristics of atomic vacancies in phosphorene, understanding their evolutions becomes crucial for its structural integrity, chemical activities and applications. Herein, by combining first-principles calculations and kinetic Monte Carlo simulation, we investigate the time evolution and formation of atomic vacancy clusters from isolated monovacancies (MVs), aiming to uncover the mechanisms of diffusion, annihilation, reaction of these atomic vacancies. We find that while isolated MVs possess a highly mobile character, they react and form MV pairs which possess much lower mobility and high stability under ambient condition. We also show that the disappearance of MVs at the edge is quite slow due to the relatively high energy barrier, and as a result, around 80% of MVs remains even after two years under ambient condition. Our findings on one hand provide useful information for the structural repairing of phosphorene through chemical functionalization of these vacancy clusters, and on the other hand, suggest that these rather stable vacancy clusters may be used as an activated catalyst.