Silver nanowires of a few nanometers across are proving to be versatile electronic component of a sensitive explosives detector according to researchers of University of California, Berkeley. The researchers made about a trillion silver nanowires essentially nanoscopic needles and packed them tightly together in a thin layer, all needles pointing in the same direction. The layer of ordered nanowires made an ideal site for chemicals to bind for detection by a very sensitive technique called surface-enhanced Raman spectroscopy. Uses This nanowire-based sensing scheme could have significant implications in chemical and biological warfare detection, national and global security, as well as medical detection applications.

A monolayer of silver nanowires makes a very sensitive substrate on which to detect molecules like DNT (dinitrotoluene, a cousin to TNT), which is used in making essentially all explosives, including land mines. Those explosives have DNT vapor coming out, allowing to do airborne detection. A microscopic sensor on a chip can be made foe very sensitive and specific detection of chemicals like explosives.

The packed silver nanowires are a better surface for enhanced Raman spectroscopy than a thin layer of silver because the nanowire surface is more ordered and gives a more clearly defined signal, making interpretation of the Raman vibrational spectrum easier. The packed silver nanowires are uniform, reproducible and suitable for use in air or in liquid.