Emory physical chemist Tim Lian researches light-driven charge transfer for solar energy conversion.Photo credit: Bryan Meltz, Emory Photo/VideoChemists have found a new, more efficient method to perform light-driven reactions, opening up another possible pathway to harness sunlight for energy. The journal Science is publishing the new method, which is based on plasmon – a special motion of electrons involved in the optical properties of metals.

"We've discovered a new and unexpected way to use plasmonic metal that holds potential for use in solar energy conversion," says Tim Lian, professor of physical chemistry at Emory University and the lead author of the research. "We've shown that we can harvest the high energy electrons excited by light in plasmon and then use this energy to do chemistry."

Plasmon is a collective motion of free electrons in a metal that strongly absorbs and scatters light.

One of the most vivid examples of surface plasmon can be seen in the intricate stained glass windows of some medieval cathedrals, an effect achieved through gold nano-particles that absorb and scatter visible light. Plasmon is highly tunable: Varying the size and shape of the gold nano-particles in the glass controls the color of the light emitted.

Modern-day science is exploring and refining the use of these plasmonic effects for a range of potential applications, from electronics to medicine and renewable energy.

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