A close-up view of an individual tree won’t tell you much about what’s going on in the forest, or even what’s going on in the tree’s upper branches. The same goes for studying nanoparticles. What is happening in one small area might not be indicative of what’s going on with the nanoparticle as a whole. In fact, the light you shine on the area may actually affect the reaction processes, giving a skewed reading.
Researchers at the National Institute of Standards and Technology (NIST) have developed a relatively simple setup that makes it possible for scientists to image simultaneously nanoscale features and microscale (nano x 1,000) chemical interactions. Their approach combines two powerful analysis tools: environmental scanning transmission electron microscopy (ESTEM)—a variation on traditional electron microscopes that enables researchers to view a specimen in a reactive environment,i.e., not in a vacuum—and Raman spectroscopy, which uses light interactions to identify molecular structures from their characteristic vibrations.
Having such a global view of nanoparticles would be useful to scientists working in a broad range of research areas from nanotechnology to pharmaceuticals and biotechnology.
The group used the technique during recent experiments to image carbon nanotubes as they germinated and grew on the surface of cobalt carbide nanoparticles.
STEM image of gold nanoparticle -- On the left, a STEM image of a triangular gold nanoparticle sitting on titanium oxide surface. The white circle at the top corner of the gold nanoparticle indicates where the electron beam is making spectroscopic measurements. On the right are the corresponding spectra representing electron absorption and emission.
Ultramicroscopy - Vibrational and optical spectroscopies integrated with environmental transmission electron microscopy