Open menu

Nanotechnology General News

The latest news from academia, regulators
research labs and other things of interest

Posted: Jun 18, 2012

Graphene decoupling of organic/inorganic interfaces

(Nanowerk News) Cryogenic ultrahigh vacuum scanning tunneling microscopy (STM) was employed by researchers in the Center for Nanoscale Materials' Electronic & Magnetic Materials & Devices Group to uncover exceptionally weak molecule-surface interactions between fullerene C60 deposited onto epitaxially grown graphene on silicon carbide substrates (see paper in Nano Letters: "Structural and Electronic Decoupling of C60 from Epitaxial Graphene on SiC").
STM three-dimensional rendered image of a C60 self-assembled monolayer at a domain boundary of graphene and bare SiC(0001)
STM three-dimensional rendered image of a C60 self-assembled monolayer at a domain boundary of graphene and bare SiC(0001); each C60 molecule is 1 nm in diameter.
The first layer of C60 molecules self-assembles into well-ordered close-packed islands. In situ scanning tunneling spectroscopy reveals a highest occupied molecular orbital–lowest unoccupied molecular orbital gap of 3.5 V, which is close to the value of solid and gas-phase C60. This finding indicates a significantly smaller amount of charge transfer from the C60 to the graphene as compared with C60 adsorbed onto metallic surfaces.
Usually interface effects dominate over the properties of adsorbed molecules. Here, however, a perfect two-dimensional material (graphene) has completely decoupled the organic system from the charged interface states of the silicon carbide surface reconstruction. Improving molecule-based organic photovoltaics and biosensors relies on minimal substrate-molecule interaction to preserve intrinsic molecular functionalities, which was achieved in this case via an inert graphene "barrier" layer.
Source: Argonne National Laboratory
If you liked this article, please give it a quick review on reddit or StumbleUpon. Thanks!
Check out these other trending stories on Nanowerk:

Subscribe to a free copy of one of our daily
Nanowerk Newsletter Email Digests
with a compilation of all of the day's news.