Molecular monolayer stabilizer for multilayer 2D materials

TL;DR

This paper demonstrates that linear alkylamines form protective monolayers on 2D materials like black phosphorous, significantly enhancing their stability against environmental degradation by selectively blocking water molecules.

Contribution

It introduces a novel molecular monolayer stabilizer using linear alkylamines for protecting 2D materials from corrosion and environmental damage.

Findings

Monolayer coatings extend black phosphorous lifetime from hours to months.

The monolayers selectively block water, acting as a drying layer.

The coating is stable in air, hydrogen, and organic solvents.

Abstract

2D van der Waals materials have rich and unique functional properties, but many are susceptible to corrosion under ambient conditions. Here we show that linear alkylamines are highly effective in protecting the optoelectronic properties of these materials such as black phosphorous (BP) and transitional metal dichalcogenides. As a representative example, n-hexylamine can be applied in the form of thin molecular monolayers on BP flakes with less-than-2nm thickness and can prolong BP's lifetime from a few hours to several weeks and even months in ambient environments. Characterizations combined with our theoretical analysis show that the thin monolayers selectively sift out water molecules, forming a drying layer to achieve the passivation of the protected 2D materials. The monolayer coating is also stable in air, hydrogen annealing, and organic solvents, but can be removed by certain organic acids.