Abstracts Book - IMRC 2018

• SA6-P137
SURFACE ENHANCED RAMAN SCATTERING DUE TO INTERSTITIAL
GOLD NANOPARTICLES INTO SiO2 SPHERES ARRAY
Miller Toledo Solano 1 , Luis A. Romero Cruz 1 , A. Santos Gómez 1 , M. A. Palomino Ovando 1 , E.
Sanchéz Mora 2 , A. L. González 2
1
Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Físico Matemáticas,
Mexico. 2 Benemerita Universidad Autonoma de Puebla, Instituto de Física BUAP, Mexico.
Films of SiO2 spheres in a periodic array infiltrated with Au nanoparticles (NPs),
were obtained by the co-assembly method. Samples with low (M1), medium
(M2) and high (M3) concentrations of Au NPs were characterized by SEM, TEM
and UV-Vis and Raman Spectroscopies. The images the microscope show that
the average size is 275 nm and 22 nm for SiO2 sphere and Au NP, respectively.
Also, with the infiltration procedure the NPs form clusters and reside in the
interstitial sites of the FCC array without modifying significantly the distance
between the centers of the SiO2 spheres. However, the photonic band gap is
shifted to larger wavelengths compared to the bare SiO2 Film. These samples
are proposed as SERS substrates, and to evidence their sensitivity, Methylene
Blue was used as the molecular probe at di↵erent concentrations. An
Enhancement Factor, EF, of ~10^5 is reached when the M3 film is used as SERS
substrate. To have an insight about the Au NPs concentration effect in the SERS
EF, discrete dipole approximation was employed to calculate the near electric
field intensity of a system of SiO2 spheres and Au NPs, observing that the near
field is more intense in the region between the SiO2 sphere surface and the Au
NPs close to it.
Acknowledgment:
This work was supported by the CONACYT-Cátedras project 3208.
Keywords: Silica Films, Gold Nanoparticles, SERS
Presenting authors email: miller.toledo@gmail.com