According to study reported in the Journal of the American Chemical Society, a team of researchers working on surface-enhanced Raman spectroscopy (SERS) developed a nanoruler to throw light on the longitudinal plasmonic fields in nanocavities.
SERS is a very effective and sensitive spectrum analysis method that may be used in a variety of disciplines. SERS generates a greatly amplified Raman signal of up to 1010-15, allowing the investigation of single molecules, in contrast to weak Raman scattering.
“To a considerable extent, how we develop the technology hinges on our understanding of plasmonic fields. In the experiments, we saw that the plasmonic field at the nanoscale was distributed unevenly. However, it is not supported by theory or experiment.
Yang declared that “strong instruments are required.” Yang and his colleagues had to devise a method of measuring plasmonic field exploration from the outset of the investigation. So, in order to examine it with great spatial resolution, we created and made the nanoruler.
A plasmonic nanocavity was created by mixing ultra-smooth gold sheets and single gold nanoparticles to create a novel nanoruler with a spatial resolution of roughly 7 x 10–10 m.
They also created the spacer layer, a unique and ground-breaking five-layer two-dimensional atomic crystal structure, in which they placed a monolayer of WS2 as a SERS probe and the remaining four layers of WS2 as reference layers.
This unique design produced a strong enough quantitative SERS intensity to directly and quantitatively determine the distribution of the longitudinal plasmonic field.
The researchers extended and confirmed their findings with theoretical derivations, computations, and spectrum measurements in addition to manufacturing and direct experimentation. Their findings demonstrate the uneven distribution and unexpectedly substantial intensity gradient of the longitudinal plasmonic field within a single nanocavity.