Article
Thermo-optical properties of gold nanoparticles in colloidal systems
Autor
Ortega, Maria Alejandra
Rodriguez, Luis
Castillo, Jimmy
Piscitelli, Vincent
Echevarria, Lorenzo
Institución
Resumen
In this work, we report the thermo-optical properties of nanoparticles in colloidal suspensions.
Spherical gold nanoparticles obtained by laser ablation in condensed media were characterized
using thermal lens spectroscopy pumping at 532 nm with a 10 ns pulse laser-Nd-YAG system.
The obtained nanoparticles were stabilized in the time by surfactants (sodium dodecyl sulfate or
SDS) in water with different molar concentrations. The morphology and size of the gold
nanoparticles were determined by transmission electron microscopy (TEM) and UV–visible
techniques. The plasmonic resonance bands in gold nanoparticles are responsible for the light
optical absorption, and the positions of the absorption maximum and bandwidth in the
UV–visible spectra are given by the morphological characteristics of these systems. The
thermo-optical constants such as thermal diffusion, thermal diffusivity, and (dn/dT) are
functions of the nanoparticle sizes and the dielectric function of the media. For these reasons,
the thermal lens (TL) signal is also dependent on nanoparticle sizes. An analysis of the TL
signal of the nanoparticles reveals the existence of an inverse dependence between the
thermo-optical functions and the size. This methodology can be used in order to evaluate these
systems and characterize nanoparticles in different media. These results are expected to have an
impact in bioimaging, biosensors, and other technological applications such as cooling systems. FONACIT (Grant G97000593) and
DID-USB (Grants S1-IC-CB-008-06 and S1-IN-CB-002-07)