Picoyune

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Picoyune was founded in 2013 by Jay James PhD and Jeffrey Crosby PhD. Their research and development at Picoyune is a continuation of fundamental research conducted at UC Berkeley and Lawrence Berkeley National Laboratory. Picoyune has received grants from the NIH, NSF, ConservationXLabs, and DOE. Picoyune is located in Berkeley, California.

Gold nanoparticle films are powerful tools for mercury analysis. Noble metal nanoparticles exhibit absorbance peaks in the visible range due to a phenomenon called localized surface plasmon resonance (LSPR). Picoyune uses gold nanoparticles with peak absorption of ~520nm. This peak is sensitive to the particle size, shape, composition, and local index of refraction. Exposure of gold nanoparticles to mercury vapor causes a blue shift in the peak.

Picoyune’s innovation of applying LSPR to mercury is uniquely sensitive. Rather than cause a change in the local index of refraction, adsorbed mercury directly contributes to the LSPR of the gold/amalgam particles. Unlike other vapor species, mercury has the conduction band electrons needed to participate in plasmon resonance.

Gold, while largely inert, readily adsorbs mercury. Selective adsorption of mercury by gold is used in mercury analysis for trapping and concentrating mercury vapor. In plasmonic mercury sensing, this selective adsorption improves sensitivity, selectivity, and stability.

To summarize, plasmonic mercury sensing with gold nanoparticles has the benefit of a combination of selective mercury adsorption and the high sensitivity of the absorption peak to amalgamation.