A team that included researchers at the Department of Energy's Oak Ridge National Laboratory used a new twist on an old method to detect materials at some of the smallest amounts yet recorded.
The results could lead to enhancements in security technology and aid the development of quantum sensors.
The study, published in Nano Letters, employed the Seebeck effect, a thermoelectric phenomenon discovered two centuries ago, to identify the heat and light signatures of molecules measured by the attogram—a quintillionth of a gram, or 1018 times lighter than a dollar bill. The heaviest amount weighed around 52 attograms, and the lightest around 40 attograms.
"It's essentially the first time that someone has reported a detection of the spectroscopic signal at those levels for that little material under ordinary conditions," said Ali Passian, an ORNL research scientist and co-author of the study.
"The technique itself is not new. But exploring the physics of sensing and asking the right question are the key. This discovery could pave the way for widespread deployment of cheap, reliable and accurate sensors for a wide variety of uses."
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