New insights into the covalent functionalization of black and blue phosphorene

Abstract

Herein, we studied the reactivity of black and blue phosphorene. They presented similar reaction energies, except for sulfur, benzynes, and nitrenes, which were more strongly bound to blue-phosphorene. Phosphorene is significantly more reactive than graphene and hexagonal-BN. The reaction energies did not reveal a significant variation for coverages around 6–1.5 %, for black-phosphorene. However, if the functional groups are agglomerated, reaction energies were improved by 16–17 kcal/mol. For blue-phosphorene, carbenes or nitrenes can promote significant structural changes at lower coverages, which are manifested by the appearance of three and five-membered rings. We provide evidence that the reported covalent functionalization of phosphorene with azodiisobutyronitrile radicals does not occur as physisorption is preferred. Nitrenes and carbenes do not undergo a [2 + 1] cycloaddition, favoring the formation of open structures. Organic reagents and sulfur are the functional groups that can pave the way toward synthesizing phosphorene monolayers with superior stability.