Covalent Functionalization and Passivation of Exfoliated Black Phosphorus via Aryl Diazonium Chemistry

TL;DR

This paper demonstrates that covalent aryl diazonium functionalization can prevent degradation of exfoliated black phosphorus and enhance its electronic properties, making it more suitable for nanoelectronic applications.

Contribution

It introduces a covalent functionalization method that stabilizes black phosphorus and tunes its electronic properties, a novel approach for its chemical modification.

Findings

Suppresses black phosphorus degradation in ambient conditions

Achieves tunable p-type doping and improved transistor performance

Reveals reaction rate dependence on aryl substituents

Abstract

Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical, and electronic properties. Exfoliated black phosphorus, a layered two-dimensional semiconductor exhibiting favorable charge carrier mobility, tunable bandgap, and highly anisotropic properties, is chemically reactive and degrades rapidly in ambient conditions. In contrast, here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated black phosphorus even following weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent, and alters the electronic properties of exfoliated black phosphorus, ultimately yielding a strong, tunable p-type doping that simultaneously improves field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated black phosphorus, thus improving its prospects for nanoelectronic applications.