Recently I starting a collaboration destined to design a suitable substrate for SERS (Surface Enhanced Raman Spectroscopy) with the help of metallic nanoparticles supported onto a substrate, and we try to control the distance between contiguous nanoparticles, promoting the formation of hot-spots where we expect to find high enhancement of the electric field.
In the research team I´m collaborating with Prof. Elías Pérez and Dr. Francisco Castillo-Rivera in the experimental part, and my contribution to the project is in the theoretical and numerical part, providing numerical simulations to give light for the realization of experiments, as well as explaining them. Currently, in the project, is working Juan Pablo López-Neira and José Mario Galicia Hernández, both PhD students (the last one under my supervision), and we recently published a paper in the Journal of Physical Chemistry A. In this work we studied the RAMAN signal coming from an amino acid in the presence of gold nanoparticles, and we compared the signal with a more elaborated substrate consisting of gold nanoparticles linked to a gadolinium particle through the amino acid, and the linked to a second gold nanoparticle, forming a trimer Au-Gd-Au being the amino acid the linker. We found an increase of five times for the signal coming from the system, that can be attributed to the contribution of the Gd particle as well as to the hot-spots generated in the substrate by the agglomeration of the gold nanoparticles.
Currently, we are working in development of a SERS substrate with coated gold nanoparticles with a tiny shell of silicon dioxide, forming spherical nanoshells. We are performing numerical calculations for the scattering efficiency of a dimer system consisting of two Au-SiO2 nanoshells, and we are trying to optimize both the thickness of the silicon dioxide shell and the separation distance of the particles in the dimer. These calculations are currently performed by José Mario Galicia-Hernández as part of his PhD thesis training.
