Selective Chemical Modification of Graphene surfaces: Distinction between Single and Bilayer Graphene

TL;DR

This study investigates the selective chemical modification of single and bilayer graphene surfaces using aromatic diazonium ions, revealing distinct reaction pathways and reactivity differences between the two types of graphene.

Contribution

It demonstrates a method for selective covalent modification of single layer graphene and highlights the contrasting behavior in bilayer graphene.

Findings

Selective derivatization of single layer graphene achieved.

Bilayer graphene forms intermediates without covalent attachment.

Reaction pathways differ significantly between single and bilayer graphene.

Abstract

Graphene modifications with oxygen or hydrogen are well known in contrast to carbon attachment to the graphene lattice. The chemical modification of graphene sheets with aromatic diazonium ions (carbon attachment) is analyzed by confocal Raman spectroscopy. The temporal and spatial evolution of surface adsorbed species allowed accurate tracking of the chemical reaction and identification of intermediates. The controlled transformation of sp2 to sp3 carbon proceeds in two separate steps. The presented derivatization is selective for single layer graphene and allows controlled transformation of adsorbed diazonium reagents into covalently bound surface derivatives with enhanced reactivity at the edge of single layer graphene. On bi-layer graphene the derivatization proceeds to an adsorbed intermediate without further reaction to form a covalent attachment on the carbon surface.