Reversible Pressure-Induced Partial Phase Transition in Few-Layer Black Phosphorus

Abstract

The experimental identification of structural transitions in layered black phosphorus (BP) under mechanical stress is essential to extend its application in microelectromechanical (MEMS) devices under harsh conditions. High-pressure Raman spectroscopic analysis of BP flakes suggests a transition pressure at ∼4.2 GPa, where the BP’s crystal structure progressively transforms from an orthorhombic to a rhombohedral symmetry (blue phosphorus, bP). The phase transition has been identified by observing a transition from blueshift to redshift of the in-plane characteristic Raman modes (B2g and Ag 2) with increasing pressure. Recovery of the vibrational frequencies for all three characteristic Raman modes confirms the reversibility of the structural phase transition. First-principles calculations provide insight into the behavior of the Raman modes of BP under high pressure and reveal the mechanism responsible for the partial phase transition from BP to bP, corresponding to a metastable equilibrium state where both phases coexist.

Simulated Raman spectra of bulk and low-dimensional phosphorus allotropes

“…). These qualitatively match those recorded in our experiment and those reported in literature 3,45,48 .…”

Vibrational Properties of Pristine and Lithium‐Intercalated Black Phosphorous under High‐Pressure

“…Kundu et al. [ 25 ] also report a similar temporary downshift for few‐layer BP under high‐pressure. They further claim that this observation as evidence for a partial phase transition from black to blue phosphorous.…”

“…However, it has been found by several previous high pressure studies on BP [ 25,23 ] that d ω /d P values for each vibrational mode depends heavily on the number of layers in the sample as well as the presence of guest species introduced by intercalation. A summary of d ω /d P values for differently layered BP samples are compared in Table 1 .…”

“…Furthermore, several works have been focused on the investigation of possible pressure‐induced structural phase transition of BP. [ 24–27 ]…”

A Critical Review on Black Phosphorus‐Based Photocatalytic CO2 Reduction Application

“…[109] Copyright 2014, American Physical Society Typically, the BP nanosheets were received from bulk BP materials via a series of physical or chemical technical means, while bulk BP materials were usually fabricated by WP or RP as the original source via phase-transformation reaction procedures. [113] In 1914, Bridgeman first obtained bulk BP materials via WP phase-transformation reaction under high pressure (up to 1.2 GPa) and high temperature (up to 200 °C). [114] Subsequently, after constant exploration and discovery, the polycrystalline BP crystals were prepared by Keyes and coauthors in 1950s by adopting higher pressure conditions (1.3 GPa).…”