Interesting Properties of Strained or Defective Graphene

Kian Ping Loh

Department of Chemistry and Graphene Research Centre, 3 Science Drive 3, Singapore, Singapore

Most people think of graphene as a flat membrane and the quality of physics
observation depends on the flatness of it. However defective or strained graphene can
present interesting properties, especially to a chemist. For example, generating pores or
voids in graphene, oxidizing and disrupting the conjugation, as in the case of
nanoporous graphene oxide, can generate a material that is catalytically active – what
the chemists called “carbocatalyst”. Nanoporous graphene oxide can mediate a wide
range of chemical transformation. We have managed to identify a simple chemical
treatment to introduce porosity and tune the acidity of Graphene Oxide (GO). This is a
potentially important area for industrial applications [1].

Generating strain textures on graphene allows the engineering of new energy landscape.
The Dirac electrons in graphene couples to strain via pseudomagnetic field, creating an
electrodynamics that is controlled by the geometry of the strain. Using the graphene
Moiré superlattice, geometrically precise nanobubbles can be generated that show
pseudomagnetic field in the hundreds of Telsa [2]. We discuss the chemistry of how
such strain texture can be created by controlling sub-surface defects on the metal
substrate. Nanobubbles on graphene can also be created when graphene is transferred
onto diamond. Very robust interfacial bonding between diamond and graphene allows a
hydrothermal anvil to be created at the interface. Superheated water trapped at the
interface becomes corrosive at high temperature and pressure and can etch diamond [3].

1.Transforming Graphene Moire Blisters to Geometric Nanobubbles
Jiong Lu, A. H. Castro Neto and Kian Ping Loh*
Nature Communications 8;3: (2012) 823.
2.Probing the Catalytic Activity of Graphene Oxide and its origin,
Chen Liang Su and Kian Ping Loh* et. al.,
Nature Communications, 3, (2012) 1298
3. A hydrothermal Anvil made of Graphene nanobubbles on diamond
Candy Su, Kian Ping Loh et. al.*
Nature Communications (2013), 10.1038/ncomms 2579.