Understanding and controlling the substrate effect on graphene electron-transfer chemistry via reactivity imprint lithography.
Graphene has exceptional electronic, optical, mechanical and thermal properties, which provide it with great potential for use in electronic, optoelectronic and sensing applications. The chemical functionalization of graphene has been investigated with a view to controlling its electronic properties and interactions with other materials. Covalent modification of graphene by organic diazonium salts has been used to achieve these goals, but because graphene comprises only a single atomic layer, it is strongly influenced by the underlying substrate. Here, we show a stark difference in the rate of electron-transfer reactions with organic diazonium salts for monolayer graphene supported on a variety of substrates. Reactions proceed rapidly for graphene supported on SiO(2) and Al(2)O(3) (sapphire), but negligibly on alkyl-terminated and hexagonal boron nitride (hBN) surfaces, as shown by Raman spectroscopy. We also develop a model of reactivity based on substrate-induced electron-hole puddles in graphene, and achieve spatial patterning of chemical reactions in graphene by patterning the substrate.
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts                 02139, USA.
Qing Hua
QH
Wang
Zhong
Z
Jin
Ki Kang
KK
Kim
Andrew J
AJ
Hilmer
Geraldine L C
GL
Paulus
Chih-Jen
CJ
Shih
Moon-Ho
MH
Ham
Javier D
JD
Sanchez-Yamagishi
Kenji
K
Watanabe
Takashi
T
Taniguchi
Jing
J
Kong
Pablo
P
Jarillo-Herrero
Michael S
MS
Strano