GOLDEN AND SUPER TOO — Sandia researcher Hongyou Fan holds a vial of gold supercrystals he is preparing to characterize in a small-angle X-ray scattering instrument (the horizontal bar). Behind him is the large chamber in which his samples are placed during supercrystal experiments.
Improved sensitivity could improve security in public places
Using an artful combination of nanotechnology and basic chemistry, Sandia researchers have encouraged gold nanoparticles to self-assemble into unusually large
Other researchers previously reported forming gold
The benchtop sensors, recently reported in Nature Communications, also are surprisingly inexpensive, Hongyou says. “The
To form each of the Sandia
Crystal facets ‘bay’ like hounds
The facets are also adept at recognizing and transmitting signals.
The initial formation of the crystals involves dispersing gold particulates about 5 nanometers in diameter into a “good” solvent, toluene. They then are subjected to a bath in a “hostile” solvent, isopropanol, which the particles supersaturate and from which they are then ejected or precipitated.
The ejected particles, refugees from the solution, then crystallize as small seeds. The growth of facets makes them available to respond to a wide variety of incoming chemical odors or light band frequencies.
The proper concentrations of materials and particle immersion times are important factors in creating large crystals. The process may take as long as a week.The work was funded by the DOE’s Basic Energy Sciences office and by Sandia’s Laboratory Directed Research and Development program. Work was carried out in part at the Center for Integrated Nanotechnologies, a DOE Office of Science user facility jointly managed by Sandia and Los Alamos national laboratories.