Raman measurements were carried out
using a Jobin-Yvon Labram HR800 spectrometer equipped with a 600-groove/mm
holographic grating, a Peltier-cooled CCD detector (1024 × 256
pixels), and an Olympus BX40 microscope with a long distance 50×
objective. The numerical aperture is equal to 0.5. A Nd:YAG laser
(532 nm) was used in all measurements. The laser power at the sample
is approximately 1 mW. A solution of 50 mM pyridine in 0.1 M KCl was
used as the probe molecule for the SERS investigations. A volume of
200 μL of the pyridine solution was deposited onto the prepared
substrates, and then the SERS spectra were recorded before the drop
dried. It should be noted here that, after the drop of the pyridine
solution has dried, the intensity of the measured SERS signal is very
irreproducible since the formed small crystals of salt disturb the
path of the incident and the scattered light. Thus, the SERS measurements
were carried out only for substrates covered with the layer of pyridine
solution. The laser spot size was approximately 1 μm2.
Pyridine spectra were performed for all of the substrates,
the electrochemically roughened silver electrode, and the nanoparticles.
The 400 spectra in an area of 60 × 60 microns were taken and
averaged. For all of these measurements, the acquisition time of a
single spectrum was 1 s. These spectra were taken also to compare
the background.
using a Jobin-Yvon Labram HR800 spectrometer equipped with a 600-groove/mm
holographic grating, a Peltier-cooled CCD detector (1024 × 256
pixels), and an Olympus BX40 microscope with a long distance 50×
objective. The numerical aperture is equal to 0.5. A Nd:YAG laser
(532 nm) was used in all measurements. The laser power at the sample
is approximately 1 mW. A solution of 50 mM pyridine in 0.1 M KCl was
used as the probe molecule for the SERS investigations. A volume of
200 μL of the pyridine solution was deposited onto the prepared
substrates, and then the SERS spectra were recorded before the drop
dried. It should be noted here that, after the drop of the pyridine
solution has dried, the intensity of the measured SERS signal is very
irreproducible since the formed small crystals of salt disturb the
path of the incident and the scattered light. Thus, the SERS measurements
were carried out only for substrates covered with the layer of pyridine
solution. The laser spot size was approximately 1 μm2.
Pyridine spectra were performed for all of the substrates,
the electrochemically roughened silver electrode, and the nanoparticles.
The 400 spectra in an area of 60 × 60 microns were taken and
averaged. For all of these measurements, the acquisition time of a
single spectrum was 1 s. These spectra were taken also to compare
the background.