# New allotropes of phosphorene with remarkable stability and intrinsic piezoelectricity

## TL;DR

This paper introduces new stable two-dimensional phosphorus allotropes assembled from nanotubes, exhibiting remarkable stability, tunable electronic properties, and intrinsic piezoelectricity, with potential applications in nano-electronics and energy harvesting.

## Contribution

It presents a novel class of 2D phosphorus allotropes constructed from nanotubes, demonstrating their stability and piezoelectric properties through first-principles calculations.

## Key findings

- New 2D phosphorus allotropes are more stable than known forms.
- Some allotropes are dynamically stable semiconductors.
- Allotropes exhibit strain-tunable band gaps and intrinsic piezoelectricity.

## Abstract

In this letter, we show that a new class of two-dimensional phosphorus allotropes can be constructed via assembling the previously proposed ultrathin metastable phosphorus nanotube into planar structures in different stacking orientations. Based on first-principles method, the structures, stabilities and fundamental electronic properties of these new two-dimensional phosphorus allotropes are systematically investigated. These two-dimensional phosphorus allotropes possess remarkable stabilities due to the strong inter-tube van der Waals interactions, which cause an energy release of about 30-70 meV/atom depending on their stacking manners. Our results show that most of these two-dimensional van der Waals phosphorene allotropes are energetically more favorable than the experimentally viable black alpha-P and blue beta-P. Three of them showing relatively higher probability to be synthesized in future are further confirmed to be dynamically stable semiconductors with strain-tunable band gaps and remarkable piezoelectricity, which may have potential applications in nano-sized sensors, piezotronics, and energy harvesting in portable electronic nano-devices.