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.
@article{arxiv.1906.00458,
title = {Molecular monolayer stabilizer for multilayer 2D materials},
author = {Cong Su and Zongyou Yin and Qing-Bo Yan and Zegao Wang and Hongtao Lin and Lei Sun and Wenshuo Xu and Tetsuya Yamada and Xiang Ji and Nobuyuki Zettsu and Katsuya Teshima and Jamie H. Warner and Mircea Dincă and Juejun Hu and Mingdong Dong and Gang Su and Jing Kong and Ju Li},
journal= {arXiv preprint arXiv:1906.00458},
year = {2019}
}