(Image credit: Michal Vadai) (Image credit: Michal Vadai)

Watching nanoparticle photoreactions

Stanford researchers retooled an electron microscope to work with visible light and gas flow, making it possible to watch a photochemical reaction as it swept across a nanoparticle the size of a cold virus.

This research focuses on a photocatalytic reaction where energy from visible light initiates a chemical reaction in nanocubes of palladium. Each of these cubes is about 30 nanometers on each side – roughly the size of a cold virus. Scientists know a lot about photocatalysis based on large groups of nanoparticles, but the new technique allows researchers to study what occurs in individual nanoparticles. Beyond photocatalysis, this technique could someday be used to study almost any interaction of light and matter with a resolution of about 2 nanometers, even those that occur in living cells.

“One of the biggest achievements of this paper is the technique itself,” Dionne said. “We bring light of various ‘colors’ to the electron microscope. Our measurements are direct – one can visibly see the photochemical reaction as it unfolds within the nanoparticle.”

Visible Legacy Comment

This research was funded by Chi-Chang Kao at SLAC National Accelerator Laboratory, a postdoctoral fellowship from the TomKat Center for Sustainable Energy at Stanford University, the Gabilan Stanford Graduate Fellowship and the National Science Foundation. With the success of this proof of concept, the lab is on to the next steps. For example, the researchers aim to add spectroscopy capabilities, which means they could evaluate the light generated from these reactions in order to analyze the chemistry in greater detail.