Electrochemical Functionalization of Graphene at the Nanoscale with Self-Assembling Diazonium Salts.
We describe a fast and versatile method to functionalize high-quality graphene with organic molecules by exploiting the synergistic effect of supramolecular and covalent chemistry. With this goal, we designed and synthesized molecules comprising a long aliphatic chain and an aryl diazonium salt. Thanks to the long chain, these molecules physisorb from solution onto CVD graphene or bulk graphite, self-assembling in an ordered monolayer. The sample is successively transferred into an aqueous electrolyte, to block any reorganization or desorption of the monolayer. An electrochemical impulse is used to transform the diazonium group into a radical capable of grafting covalently to the substrate and transforming the physisorption into a covalent chemisorption. During covalent grafting in water, the molecules retain the ordered packing formed upon self-assembly. Our two-step approach is characterized by the independent control over the processes of immobilization of molecules on the substrate and their covalent tethering, enabling fast (t < 10 s) covalent functionalization of graphene. This strategy is highly versatile and works with many carbon-based materials including graphene deposited on silicon, plastic, and quartz as well as highly oriented pyrolytic graphite.
Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , via Gobetti 101, 40129 Bologna, Italy.
Zhenyuan
Z
Xia
Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , via Gobetti 101, 40129 Bologna, Italy.
Francesca
F
Leonardi
ISIS and icFRC Université de Strasbourg and CNRS , 8 Allée Monge, 67000 Strasbourg, France.
Marco
M
Gobbi
Max Planck Institute for Polymer Research , Ackermannweg 10, Mainz 55128, Germany.
Yi
Y
Liu
Dipartimento di Fisica, Università degli Studi di Pavia , via Bassi 6, 27100 Pavia, Italy.
Vittorio
V
Bellani
Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , via Gobetti 101, 40129 Bologna, Italy.
Andrea
A
Liscio
Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , via Gobetti 101, 40129 Bologna, Italy.
Alessandro
A
Kovtun
Max Planck Institute for Polymer Research , Ackermannweg 10, Mainz 55128, Germany.
Rongjin
R
Li
Max Planck Institute for Polymer Research , Ackermannweg 10, Mainz 55128, Germany.
Xinliang
X
Feng
ISIS and icFRC Université de Strasbourg and CNRS , 8 Allée Monge, 67000 Strasbourg, France.
Emanuele
E
Orgiu
ISIS and icFRC Université de Strasbourg and CNRS , 8 Allée Monge, 67000 Strasbourg, France.
Paolo
P
Samorì
Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , via Gobetti 101, 40129 Bologna, Italy.
Emanuele
E
Treossi
Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , via Gobetti 101, 40129 Bologna, Italy.
Vincenzo
V
Palermo
diazonium salts; electrochemistry; graphene; self-assembly