Excitons observed in action for the first time (MIT News)

Insights generated by this new imaging technique could lead to significant advances in electronics, and deeper understanding about energy-transfer processes like photosynthesis.

Excitons observed in action for the first time
Technique developed at MIT reveals the motion of energy-carrying quasiparticles in solid material.

David L. Chandler | MIT News Office
April 16, 2014

A quasiparticle called an exciton — responsible for the transfer of energy within devices such as solar cells, LEDs, and semiconductor circuits — has been understood theoretically for decades. But exciton movement within materials has never been directly observed.

Now scientists at MIT and the City College of New York have achieved that feat, imaging excitons’ motions directly. This could enable research leading to significant advances in electronics, they say, as well as a better understanding of natural energy-transfer processes, such as photosynthesis.

The research is described this week in the journal Nature Communications, in a paper co-authored by MIT postdocs Gleb Akselrod and Parag Deotare, professors Vladimir Bulovic and Marc Baldo, and four others.

“This is the first direct observation of exciton diffusion processes,” Bulovic says, “showing that crystal structure can dramatically affect the diffusion process.”

“Excitons are at the heart of devices that are relevant to modern technology,” Akselrod explains: The particles determine how energy moves at the nanoscale. “The efficiency of devices such as photovoltaics and LEDs depends on how well excitons move within the material,” he adds. Read more…

Learn more about the exciton and related phenomena in these OCW courses:

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