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BRIEFS
Perpetuus Carbon Group,UK, a producer of purified and functionalized graphene, received independent
verification of its graphene production. An independent work-study using a measurement study compliant with
BS 3138:1992, concluded that the annual theoretical capacity, running 30 kg batches of raw graphite, is 140 tons
per year from a single reactor. .
Graphene has incredible intrinsic properties, showing great potential for industrial and commercial applications
across a wide range of industries. Courtesy of Haydale Ltd.
Cornhusksconverted
tosiliconcarbide
Scientists at the U.S. Naval Re-
search Laboratory (NRL), Washington,
are exploring ways to convert agricul-
tural waste into high-value silicon car-
bide that can be used for a variety of
electronic and structural applications.
Agricultural wasteproducts have signifi-
cantly high silica content in a molecular
state, similar to hydrocarbons. Armed
with that knowledge, Syed B. Qadri and
his team discovered that these agricul-
tural waste products can be econom-
ically transformed into silicon carbide
(SiC) consisting of nanostructures and
nanorods in various polytypes.
The team accomplished this by
pyrolysis of the agricultural waste to
produce the crystalline phases of sili-
con carbide, a highly stable compound,
in various shapes of nanocrystals, na-
norods, and nanowires. By selectively
heating and cooling the agricultural
waste products, they were able to sys-
tematically investigate the role of tem-
perature rise and cooling rates. They
observed that this heating and cooling
process directly impacts the extended
defect formation mechanisms that help
in modifying the optical, electrical, and
structural properties of these nanoparti-
cles. .
Newunderstandingof
nanocrystals
Nanocrystals exhibit unprecedent-
ed properties that intrigue scientists
and engineers. To apply these materials
in emerging nanotechnologies, scien-
tists need to better understand their
structure, corresponding functions, and
how they pack together. Collaboration
between Cornell High Energy Synchro-
tron Source (CHESS), Ithaca, N.Y., and
materials scientists has yielded great-
er understanding of what particular
nanocrystals look like individually and
how they fit together as they form larg-
er structures called supercrystals. This
discovery could lead to effective bot-
tom-up engineering of new materials
for applications ranging from solar cells
to electronic components.
The team used innovative x-ray
crystallography methods at the B1
CHESS beamline led by Zhongwu Wang.
Data was simultaneously collected on
the ordering and orientation of lead
sulfide nanocrystals and supercrys-
tals using both wide-angle (WAXS) and
small-angle (SAXS) x-ray scattering,
which are typically done one at a time.
The new method provides insights into
the unexpected complexity of the ar-
rangement of nanocrystals within the
supercrystal. The discovery could result
in new methods for growing supercrys-
tals and how to optimize their proper-
ties. .
NANOTECHNOLOGY
For U.S. Naval Research Laboratory scientists, the conversion of rice husks to high value SiC
nanowires may provide newmaterials for electronic and structural applications.
Northwestern
University, Evanston,
Ill., professor Mark
Hersam won a “genius
grant” from the
MacArthur Foundation for
his investigations
into how the tiniest
materials can improve
electronics, medical
devices, and renewable
energy. Hersam is using
graphene to fashion novel
devices that create new
possibilities in support
of the Office of Naval
Research plan to enhance
the Navy’s asymmetric
capabilities across the
physical domain,
cyberspace, and
electromagnetic spectrum.
.
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