6 research outputs found
Self-Organized SERS Substrates with Efficient Analyte Enrichment in the Hot Spots
One of the requirements of an efficient surface-enhanced
Raman
spectroscopy (SERS) substrate is a developed surface morphology with
a high density of “hot spots”, nm-scale spacings between
plasmonic nanoparticles. Of particular interest are plasmonic architectures
that could enable self-localization (enrichment) of the analyte in
the hot spots. We report a straightforward method of fabrication of
efficient SERS substrates that comply with these requirements. The
basis of the substrate is a large-area film of tightly packed SiO2 spheres formed by their quick self-assembling upon drop casting
from the solution. Thermally evaporated thin Ag layer is converted
by quick thermal annealing into nanoparticles (NPs) self-assembled
in the trenches between the silica spheres, i.e., in the places where
the analyte molecules get localized upon deposition from solution
and drying. Therefore, the obtained substrate morphology enables an
efficient enrichment of the analyte in the hot spots formed by the
densely arranged plasmonic NPs. The high efficiency of the developed
SERS substrates is demonstrated by the detection of Rhodamine 6G down
to 10–13 mol/L with an enhancement factor of ∼108, as well as the detection of low concentrations of various
nonresonant analytes, both small dye molecules and large biomolecules.
The developed approach to SERS substrates is very straightforward
for implementation and can be further extended to using gold or other
plasmonic NPs