Bose-Einstein condensation of excitons — in which excitons condense into a single coherent quantum state, known as an exciton condensate — enables frictionless energy transfer, but typically occurs under extreme conditions in highly ordered materials, such as graphene double layers. In contrast, photosynthetic light-harvesting complexes demonstrate extremely efficient transfer of energy in disordered systems under ambient conditions. Now, physicists have established a link between the two phenomena by investigating the potential for exciton-condensate-like amplification of energy transport in room-temperature light harvesting.
“As far as we know, these areas have never been connected before, so we found this very compelling and exciting,” said Professor David Mazziotti and his colleagues at the University of Chicago.
The team specializes in modeling the complicated interactions of atoms and molecules as they display interesting properties.
There’s no way to see these interactions with the naked eye, so computer modeling can give scientists a window into why the behavior happens — and can also provide a foundation for designing future technology.
In particular, the researchers have been modeling what happens at the molecular level when photosynthesis occurs.
When a photon from the Sun strikes a leaf, it sparks a change in a specially designed molecule. The energy knocks loose an electron.
The electron, and the ‘hole’ where it once was, can now travel around the leaf, carrying the energy of the Sun to another area where it triggers a chemical reaction to make sugars for the plant.
Together, that traveling electron-and-hole-pair is referred to as an exciton.
When the team took a birds-eye view and modeled how multiple excitons move around, they noticed something odd. They saw patterns in the paths of the excitons that looked remarkably familiar.
In fact, it looked very much like the behavior in a material that is known as a Bose-Einstein…
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