Stable Aqueous Dispersions of Optically and Electronically Active Phosphorene

TL;DR

This paper introduces a surfactant-assisted exfoliation method in deoxygenated water for producing stable, high-quality phosphorene dispersions that preserve electronic properties and enable scalable applications.

Contribution

It presents a novel aqueous exfoliation technique that yields high-quality, stable phosphorene suitable for electronic devices, overcoming limitations of organic solvent methods.

Findings

Dispersions are stable and highly concentrated.

Flakes are thinner than those from organic solvents.

Electronic properties are preserved in field-effect transistors.

Abstract

Understanding and exploiting the remarkable optical and electronic properties of phosphorene require mass production methods that avoid chemical degradation. While solution-based strategies have been developed for scalable exfoliation of black phosphorus, these techniques have thus far employed anhydrous organic solvents in an effort to minimize exposure to known oxidants, but at the cost of limited exfoliation yield and flake size distribution. Here, we present an alternative phosphorene production method based on surfactant-assisted exfoliation and post-processing of black phosphorus in deoxygenated water. From comprehensive microscopic and spectroscopic analysis, this approach is shown to yield phosphorene dispersions that are stable, highly concentrated, and comparable to micromechanically exfoliated phosphorene in structure and chemistry. Due to the high exfoliation efficiency of this process, the resulting phosphorene flakes are thinner than anhydrous organic solvent dispersions, thus allowing the observation of layer-dependent photoluminescence down to the monolayer limit. Furthermore, to demonstrate preservation of electronic properties following solution processing, the aqueous-exfoliated phosphorene flakes are employed in field-effect transistors with high drive currents and current modulation ratios. Overall, this method enables the isolation and mass production of few-layer phosphorene, which will accelerate ongoing efforts to realize a diverse range of phosphorene-based applications.