Two Dimensional Phosphorus Oxides as Energy and Information Materials

TL;DR

This study explores the structures, properties, and potential applications of 2D phosphorus oxides, revealing their stability, electronic properties, and ferroelectric behavior, indicating their promise as functional materials for energy and information technologies.

Contribution

The paper systematically characterizes 2D phosphorus oxides, identifying stable structures, electronic properties, and potential device applications, which advances understanding beyond prior work on phosphorene.

Findings

2D P4O4 has a direct band gap of ~2.24 eV and good water stability.

2D P2O3 exhibits two stable ferroelectric structures with different polarization directions.

2D phosphorus oxides are promising for photochemical and memory device applications.

Abstract

Two-dimensional (2D) black phosphorus (i.e., phosphorene) has become a rising star in electronics. Recently, 2D phosphorus oxides with higher stability have been synthesized. In this work, we systematically explore the structures and properties of 2D phosphorus oxides on the basis of global optimization approach and first-principles calculations. We find that the structural features of 2D phosphorus oxides PxOy vary with the oxygen concentration. When the oxygen content is poor, the most stable 2D PxOy can be obtained by adsorbing O atoms on phosphorene. However, when the oxygen concentration becomes rich, stable structures are no longer based on phosphorene and will contain P-O-P motifs. For the 2D P4O4, we find that it has a direct band gap (about 2.24 eV), good optical absorption, and high stability in water, suggesting that it may be good candidate for photochemical water splitting application. Interestingly, 2D P2O3 adopt two possible stable ferroelectric structures (P2O3-I and P2O3-II) as the lowest energy configurations within a given layer thickness. The electric polarizations of P2O3-I and P2O3-II are perpendicular and parallel to the lateral plane, respectively. We propose that 2D P2O3 could be used in a novel nanoscale multiple-state memory device. Our work suggests that 2D phosphorus oxides may be excellent functional materials.