1 research outputs found
Photoluminescent Nanostructures from Graphite Oxidation
The graphite intercalation compound (GIC) of 3:1 sulfuric
to nitric
acid mixture was used to produce photoluminescent (PL) nanostructures
by oxidizing micrographite, nanographite, nanographite platelets,
onion-like-carbon, and highly oriented pyrolytic graphite. The GIC
used in this work is a Stage I intercalation compound that expands
the graphitic planes to a maximum degree; this expansion was visible
as a blue color for these graphitic materials in suspension with the
GIC solution. The GIC intercalates into the graphitic layers to facilitate
oxidation, resulting in graphite oxide, which may be fully exfoliated
to graphene oxide. This treatment produced carbon nanostructures that
were colloidally stable and photoluminesced across the visible wavelength
range. It was possible to control the PL color of the reaction suspension
by tuning the reaction temperature or reaction time; higher temperatures
or longer reaction times caused a blue shift in the PL wavelength.
Various graphitic oxide nanostructures were observed in the reaction
suspension with increasing reaction time, including nanoribbons, graphene-like
nanoplatelets, and round single-digit nanoparticles. Using separation
methods for a PL orange reaction supernatant solution, it was possible
to isolate individual PL colors spanning the visible wavelength region.
These PL colors exhibit a blue shift in emission wavelength with filters
that decreased in molecular weight or as the migration distanced increased
in a denaturing polyacrylamide gel. Chemical functionalization of
the PL blue carbon product from the oxidation of nanographite platelet
allowed for the fluorescent coating of silica beads