1 research outputs found
Ultrasmall Gold Nanoparticles Anchored to Graphene and Enhanced Photothermal Effects by Laser Irradiation of Gold Nanostructures in Graphene Oxide Solutions
In this work we demonstrate the coupling of the photothermal effects
of gold nanostructures of controlled size and shape with graphene
oxide nanosheets dispersed in water. The enhanced photothermal effects
can be tuned by controlling the shape and size of the gold nanostructures,
which result in a remarkable increase in the heating efficiency of
the laser-induced size reduction of gold nanostructures. The Raman
spectra of the Au–graphene nanosheets provide direct evidence
for the presence of more structural defects in the graphene lattice
induced by laser irradiation of graphene oxide nanosheets in the presence
of Au nanostructures. The large surface areas of the laser-reduced
graphene oxide nanosheets with multiple defect sites and vacancies
provide efficient nucleation sites for the ultrasmall gold nanoparticles
with diameters of 2–4 nm to be anchored to the graphene surface.
This defect filling mechanism decreases the mobility of the ultrasmall
gold nanoparticles and, thus, stabilizes the particles against the
Ostwald ripening process, which leads to a broad size distribution
of the laser-size-reduced gold nanoparticles. The Au nanostructures/graphene
oxide solutions and the ultrasmall gold–graphene nanocomposites
are proposed as promising materials for photothermal therapy and for
the efficient conversion of solar energy into usable heat for a variety
of thermal, thermochemical, and thermomechanical applications